12 Causes of a Car That Won’t Accelerate (and How to Fix Each)

Have you ever experienced your car suddenly losing acceleration, leaving you in a dangerous situation on the highway? You’re not alone.

In this article, we’ll explore the common causes of this issue and help you understand what’s happening under the hood so you can get your car back up to speed.

reasons and causes of car not accelerating

Reasons Your Car Won’t Accelerate When You Push the Gas

Acceleration problems are a common occurrence in high mileage vehicles. But typically, there are no serious or immediate concerns regarding major engine problems. As with any car problem, potential causes that are minor should be checked first in order to locate the issue and possibly fix it as well.

Below are some of the most common culprits to a lack of acceleration. The reasons are many so if you’re not completely comfortable troubleshooting a car that won’t accelerate, we recommend you take your vehicle to a reliable mechanic and let him properly diagnose the issue.

Read Also: Symptoms of a Faulty Transmission Speed Sensor

#1 – Mass Air Flow Sensor Clogged or Malfunctioned

MAF sensor

The mass air flow sensor (or meter) is located and attached to the inlet air cleaner. Since the function of the air flow sensor is to measure air mass that is flowing into air intake, a clogged or bad mass air flow sensor could send the wrong data to the engine ECU for calculating the air fuel mixture.

A very common symptom of an air flow meter malfunction is car that struggles to pick up speed.

How to Fix: Clean or replace the MAF sensor.

#2 – Oxygen Sensor Malfunction

oxygen sensor

An oxygen sensor (aka O2 sensor) is device whose function is to monitor the exhaust emissions of the vehicle so that it can analyze the air-fuel ratio going through the engine of that vehicle.

To make a long story short, a car needs a proper amount of fuel in order for the fuel to burn properly in the combustion cylinders so that it may run smoothly and may accelerate as required.

This sensor sends the information about the amount of fuel being used to the computer unit of the engine and if this sensor get damaged, then the engine of that vehicle will have no idea what ratio of air-fuel mixture to use which may result in a fuel rich mixture.

This can cause the slow acceleration of the vehicle even with the accelerator pedal completely pressed making it unreliable when it’s needed.

How to Fix: Using an automotive scan tool, determine which sensor is malfunctioning. Replace the O2 sensor.

#3 – Malfunction of TPS

TPS sensor

The basic principle of the throttle position sensor (TPS) is to detect the throttle valve opening angle which is controlled by accelerator pedal. Then the TPS will send this data to the ECU.

If the TPS malfunctions, the engine speed cannot be controlled by the accelerator pedal and engine speed will increase or decrease without any press or depress the pedal.

How to Fix: Replace the throttle position sensor.

#4 – Dirty or Clogged Fuel Filter

fuel filter

A dirty or clogged fuel filter is another reason for a car not accelerating like it’s supposed to when required to do so.

With a dirty fuel filter, the engine won’t be getting enough fuel which means that the vehicle won’t be giving the acceleration performance that it should. Replace the fuel filter as soon as possible.

How to Fix: Replace the fuel filter.

#5 – Clogged or Dirty Air Filters

dirty air filter

Just like a fuel filter provides the engine with the clean fuel, an air filter provides the engine of a vehicle with clean air to be used in the air-fuel mixture which will be sent to the combustion chambers to burn.

If an air filter is clogged, then the engine won’t get the right air-fuel mixture resulting in slow acceleration. Replace the air filter as soon as possible.

How to Fix: Replace the air filter. If you have a reusable air filter like K&N, follow the directions on cleaning it.

#6 – Bad Fuel Injector

fuel injector replacement cost

Fuel injectors are responsible for delivering fuel to the engine, and if they’re not functioning properly, your car will likely not be able to accelerate properly. 

A dirty, clogged, damaged, or faulty fuel injector may restrict the flow of fuel to the engine, which can result in poor acceleration, hesitation, or even stalling.

How to Fix: Use a diagnostic scan tool to read error codes from the car’s computer. If the error code indicates a problem with the fuel injector, you can try cleaning it with a fuel injector cleaner. If cleaning doesn’t work, replace the fuel injector.

#7 – Limp Mode

limp home mode symptoms

Limp mode is a safety feature that is designed to protect your engine from damage. If your car’s computer detects a problem with the engine, it may put the car into limp mode, which limits the engine’s power and speed.

This undoubtedly will cause your car to have acceleration issues, and may also be accompanied by a flashing check engine light.

How to Fix: Using an OBD2 scanner, scan the car’s computer for fault codes to determine what exactly is causing the vehicle to go into limp mode.

#8 – Faulty Fuel Pump

bad fuel pump

The fuel pump is responsible for delivering fuel from the gas tank to the engine. If it’s not functioning properly, it can cause a lack of fuel pressure, which can lead to poor acceleration. Symptoms of a bad fuel pump include sputtering or stalling while driving, difficulty starting the engine, and a decrease in fuel efficiency.

How to Fix: Replace the fuel pump.

#9 – Timing Belt

bad timing belt

This component is as it sounds. The timing belt is something like a VIP in the list key of components of an engine. If this belt is off even by 1 tooth, it may cause some pretty notable acceleration problems.

How to Fix: Replace the timing belt.

#10 – Slipping Clutch

burnt clutch

If you have a manual transmission, a slipping clutch can cause acceleration problems. This happens when the clutch disc fails to engage properly with the flywheel, causing what feels like your car has lost power while driving. It’s similar to a person trying to run on ice.

Signs of a slipping clutch include a burning smell, difficulty shifting gears, and poor acceleration.

How to Fix: Replace the clutch.

#11 – ECU

ECU error

The ECU, or engine control unit, is responsible for regulating the performance of your car’s engine. If it’s malfunctioning in some way, it could be causing your car to have trouble accelerating. A faulty ECU can cause a variety of other issues, including misfires and poor fuel economy.

How to Fix: Repair or replace the ECU.

#12 – Clogged Exhaust

Two major components of your car’s exhaust system are your catalytic converter and muffler. If either one of these becomes clogged or damaged, this can restrict exhaust flow and lead to a reduction in engine power and acceleration.

This is especially the case with turbocharged vehicles which require proper exhaust flow to work as intended.

How to Fix: Check all components of the exhaust system to look for clogged or damaged parts. Replace if necessary.

Checking for Trouble Codes

If your car won’t accelerate, one of the first things you should look for is the Check Engine light. This light will come on if there is a problem with your car’s engine or emissions system. It’s worth mentioning that the Check Engine light does not always mean that there’s a major problem. Sometimes, it can be a minor issue that can be easily fixed.

To check for trouble codes, you will need an OBD2 scanner. This is a device that plugs into your car’s OBD2 port and reads the codes stored in your car’s computer. Once you’ve connected the scanner, you can retrieve the trouble codes and get a better idea of what is causing your car to not accelerate properly.

Once you see what trouble codes have been stored, you can use them for diagnosis. These codes will give you a better idea of what is causing your car to not accelerate properly.

But the fact is that trouble codes don’t always pinpoint the exact problem. In some cases, the codes may be related to a minor issue that can be easily fixed. In other cases, the codes may indicate a major problem that requires immediate attention.

If you’re unsure what the codes mean, have a mechanic diagnose further – don’t rely on the codes alone.

Acceleration Problems’ Impact on Fuel Economy

When your car won’t accelerate properly, it can have a significant impact on your fuel economy. Poor fuel economy is a common symptom of a car that won’t accelerate as it should.

You may think that if your car is accelerating poorly, it’s using less gas so your fuel economy should be better. But the opposite can actually happen!

If your car is struggling to accelerate, it means that your engine is working harder than it should, which can lead to increased fuel consumption.

Mark Stevens


  1. Thank u for this lecturing technics an am glad I contacted u for info. But how do I fix this myself because from ur explanation is the exact of what is happening to my car, A TOYOTA COROLLA 2007. Though I am good at doing it myself should I try checking all the listed component one by one to get the real fault of the low acceleration issue?

    1. You will have to narrow the problem down to the exact cause that is affecting your car. It is unlikely that all 12 causes are the reason your car is slow to accelerate. Do some diagnostics, look under the hood and inspect the engine to see if anything looks broken or out of place. Check the fuses to make sure they are all good. Things like that.

  2. I have a 2013 Chevy spark. I replaced the brakes (previous to this my car was running fine) My car will start up but it dies soon after. It’s like it don’t have enough power to run. I can put my foot all the way to the floor and it will not go over 10 MPH. I replaced the mass airflow sensor & the elbow hose because I thought that would solve the problems I was having but it hasn’t & I just really need help. I am a single mother of 2 children & can not continue to buy parts for my car that is not needed.

    1. Did you replace the brakes yourself? Sounds to me like either the problems are unrelated, or something was taken apart during the work that wasn’t put back together quite right.

      If you took it to a shop for the work, I’d take the vehicle back to them and have them take a look at it. If you did the work yourself, I’d double check your work to make sure you didn’t forget to plug anything in. It could be something simple like a vacuum hose.

  3. I have a 2006 Pontiac Vibe. After driving for a while and particular when trying to climb a hill, it stops accelerating with an accompanying and unusual heat and smell. What are the possible causes and how can I fix them?

  4. What was the problem you were experiencing before changing out all those parts? Was there any change after those replacements? Did you try both ECUs (what you call a brainbox) in the other Kia?

  5. I have a kia optima 2010 automatic.
    I just changed my fuel pump, sensor, steering rack and ECU

    But after all these my car won’t accelerate on matching down the gas and it doesn’t raise.

    My mech said it’s the ECU that he has tried to use it on another kia optima just like mine but same thing happened.

    What can I do or what could be the problem?

    1. What was the problem you were experiencing before changing out all those parts? Was there any change in vehicle behavior after those replacements? Did you try both ECUs in the other Kia?

  6. Me and my buddy both have 2008 ford crown vic 4.6 police interceptors and yesterday his mass air flow sensor went bad and every time we started the car it kill itself after 1 seconds until we took the intake off the throttle body and it would idle for 30 seconds or so then die but we replaced the maf sensor fixed everything then not even 24 hours later I’m driving 60 in my crown vic and it feels a little weird so I smashed the throttle and it seemed like I threw it in neutral and rev lined then a minute later at like 20 I kept giving it gas and went no where so I pulled off let it idle and after 30s it started loping like a cammed racecare more and more till it killed itself tried starting it immediately died, I was only a mile from home so I left the air intake open to try and get more air and it started alive back to my house but wanted to kill itself every time rps went down and would sputter till rpms where back up got home and let it idle started lopping again about to die then sounded kinda like it started knocking but couldn’t tell because I shut it off fast after I could smell oil but seemed to smell more new then burning oil. It seems kinda like the maf sensor but I just don’t believe it because we have both had the vehicles for years put over 60k miles on both and they both go bad within 24 hours. On my vic before this happened i took the driver side headlight out to replace and drove like that for a few hours at slow speeds the air intake is directly behind that head light could the more airflow damage the maf sensor or cause it to run like it did or is that unrelated I didn’t think it would be alot more airflow into the air intake but idk.

    1. That’s strange for them both to have problems right around the same time. Did you guys replace any parts around the same time that could’ve caused the issue? Aftermarket parts can cause issues on some cars if the cars are not tuned for those specific parts.

      See if you can find a scan tool to hook up and look at some live data while you drive around. That’ll help you determine if it’s an air or a fueling issue. It sounds like you suspect the MAF sensors are bad, but you’re not sure. It would be weird for both MAF sensors to go out at the same time like that.

  7. Great advice!! I have a 2005 6.0 powerstroke Ford 350 diesel. It starts and runs great. When I come to a stop after driving for about 15 minutes a wrench light come on and there is no acceleration. What could be causing this issue. I f I wait about 15 minutes the wrench goes away and I have acceleration.

  8. I have a 3s engine Rav 4 which of recent has been giving me acceleration problem. When I press the gas, the vehicle is slow to pick up. Fuel filter and air cleaner were recently changed.
    What could cause this?

    1. Rav4s don’t have a ton of power to begin with. Is the vehicle driving slower than usual? Could you be stuck in a higher gear?

  9. My 2013 Hyundai Elantra will sometimes not accelerate. I can barely get it to move and then when it is barely moving I put it in manual mode and it’s stuck on gear 4 or 5 and won’t go up or down until I drive it far enough where it will then start accerlating and the manual mode shows the gear it actually is in or I restart it and then it goes through gears fine. Sometimes it just dies when I try to accerlate. I have to turn it off and then on again, which will usually drive perfect then. When it is barely moving and I keep accelerating until it finally pushes past that point and starts to pick up speed I put it in manual to see where it is and it showed gear 6, which I don’t have 6 gears. When I restart the car and it is driving fine then manual shows the gears correctly, including gear 1. Yesterday it was driving fine and when I left an appointment it wouldn’t go into reverse. I had to restart the car and then it drove fine. It’s in the shop now & they can’t find anything wrong and says it’s not acting up for them. I don’t want to be in traffic and get into a bad accident due to this. Any suggestions?? Thank you much.

    1. Sounds like something is wrong with the transmission. I would have a transmission shop take a look at it.

  10. I have a 2015 Nissan Pathfinder..my car sometimes won’t pick up speed and rpm won’t go up and stays around 1000rpm but car still moves..I have to press on the brake a couple of times then press on the gas and it will be working fine..I changed the air filters and had my fuel injectors cleaned..what could be wrong with it?

    1. Do you have any warning lights on the dash? It sounds like the vehicle is in limp mode. If so, could you scan for codes and tell me what codes are stored in memory?

  11. My truck can start everything but if I put on drive it won’t move even I press the accelerator no power the truck just jerking we change the fuel filter but still not working and we have engine light on still I need help

  12. Hi, I have an 02 Nissan Pathfinder. In park or neutral I get the appropriate revs when I press the accelerator. But all that disappears once I put it in drive.
    Struggles to climb uphill or rev enough to go into 2nd gear. 2nd gear and more are slightly better but that delay or lack of power is still there.

    Could it be the fuel filter or something else?

    1. If it’s a fuel restriction, the issue should get worse as you give it more gas. It could be a transmission issue, where something in the transmission is causing the vehicle to struggle while accelerating.

  13. My Jeep Wrangler won’t climb hill and gas pedal feels stiff has hard time taking off please what I do

    1. Perhaps the accelerator pedal assembly is bent, or there is an obstruction that is preventing you from pushing the gas pedal or opening the throttle all the way.

  14. Hi

    I have a 2013 Fiat Punto 1.4 Easy. The car is not getting to high rpms when I rev it on idle position. When I’m driving it it’s struggling to reach high speeds and can’t go uphill. I have to change down to 2nd gear and the speed would be around 40km per hour.

    The engine code is P0016, I have done timing, bought new injectors but still it’s struggling to increase speed.

    One mechanic is suggesting that I buy a new Throttle Board. Please help.

    1. Never heard of a throttle board. Did he mean the throttle body?

      I would start by looking at the VVT system. Perhaps a cam sensor is bad or there is an issue with the electrical system leading to the cam sensor. There could be an obstruction in an oil passage that is causing issues with the VVT system as well.

  15. I’ve changed the crankshaft position sensor I’ve changed the o2 sensors the Mass air flow sensor the evap solenoid my car keep reading evap and mass airflow changed the connector what else could it be

  16. Good day… My dodge caliber will start normal but once I start to drive it select gear 2 it starts dropping speed and will not select next gears and it will move slowly no matter how I match the throttle paddle

  17. Hello, I have a 1994 3s-fe Toyota Curren. I am having an issue with my engine. The engine will not rev past 2000 rpm and seems to be a fuel cut at 2000rpm. There are also no check engine lights. When we turn on the lights (headlights etc), the engine will sometimes (not all the time) happily rev as usual. We have tried replacing the throttle position sensor. A mechanic has diagnosed the engine and received the fault code for an o2 sensor. What do you think is causing my problem? Would it be worthwhile replacing the o2 sensor? Thanks heaps

    1. It’s worthwhile to replace the O2 sensor for fuel economy alone, but I don’t necessarily think it is related to your engine not revving past 2,000 RPM. I’m not really sure what would cause that. I’m wondering if maybe there is a fueling issue where the car is not getting enough fuel to be able to make more than a certain amount of power.

      Are your revs limited both while in neutral and while driving?

  18. My nissan 2000 automatic transmission vibrates too much when in drive mode and i am not moving. Also if i accelerate slowly to 40, the acceleration becomes slow from 40 to 60 even with full pedal down. If i accelerate fast, I don’t get any problems. There are no loghts on my dashboard

    1. I wonder if the vibration could be caused by an old motor or transmission mount. Engine and transmission mounts are designed to keep unwanted noise, vibration, and harshness (NVH) out of the cabin. As your car ages, sometimes these mounts wear out. When the mounts wear out, you will feel additional vibrations and possibly some strange clunking from the powertrain.

      The 40 to 60 issue could be a matter of transmission tuning. On a lot of cars, if you don’t push the gas pedal down hard enough to get the car to downshift, the car will hardly accelerate. If you stab the throttle wide open (so the gas pedal is all the way to the floor), you can usually get the transmission to downshift to give you the power you need.

  19. My 2006 Corolla does not accelerate even after pressing down the Accelerator. I have given it to a good Auto-Electrician but he could not fix it. It just go on normal drive (0km/h).

    Please I need suggestions

    1. Could be a clogged air intake system, could be a clogged fuel filter or injectors. Could be old spark plugs. There are a lot of possibilities. Probably your best bet is to get the car to a mechanic in your area who can help you narrow down the problem.

      Does it idle rough? Are there any other symptoms you’ve noticed?

  20. Sean, please when someone states a problem they’re having with their car, the best you can do is tell what the possible causes would be instead of asking silly questions, if you want to help go straight to the point and say possible causes… Thank you

    1. I’m glad you brought this up John, as this is something I think about a lot. I would love to go straight to the point, but unfortunately, that’s often not possible.

      Many times OP does not provide sufficient information to even begin to narrow the problem down. We have to ask questions so we can arrive at an answer that is ultimately more helpful than “there’s something wrong with your car.”

      Even a good problem solver isn’t clairvoyant. It’s much worse to send someone down the wrong path assuming we understand the scope of the problem than it is to ask a few basic questions to gather additional information. Sometimes asking these questions is actually all the help OP needs. If they decide they can’t fix the issue by themselves, they can then bring their vehicle to a shop with a better understanding of what the mechanic will need to know in order to correctly diagnose the problem.

      This article is a great example of why we need to ask good questions to narrow the scope of the problem. Slow acceleration could be caused by a huge number of things, including but not limited to: bad spark plugs, bad spark plug wires, low compression, misfires, carbon build up, clogged air filter, clogged fuel filter, poor engine tuning, exhaust restriction, timing belt skipped a tooth, bad fuel, a bad sensor, or limp mode (in which case the root cause may be unrelated). That’s just off the top of my head; I know there are many more possibilities. I hope this highlights the value of asking a few questions and a little back and forth with the person having trouble.

  21. Hi. My toyota avanza drop speed as it’s ŕeach to 80kmph. The 300hrm on and then niddle of rm stay doesn’t change position. Get no power like. No error light. Up 60kmph speed it’s ok. But Don’t work as go higher speed.

    1. Hey Azar, I’m not sure I follow. Can you elaborate what you mean by “drop speed”? Does it seem to hesitate or not want to accelerate?

  22. Hi Everyone,
    I have a Hyundai Tucson 2017 and and when I push the gas paddle won’t speed no more than 45 sometimes does someone know what the problem could be?

    1. Are there any lights on the dash that are illuminated? It sounds like the vehicle may be in limp mode. If so, there should be one or more codes stored that will help you narrow down the problem. Codes can be scanned (usually for free) at most auto parts stores.

  23. I have a lexus 300. Everytime I add fuel to my car it stalls or doesn’t accelerate at all until I pour fuel injector cleanser. The injector has been cleaned but problem still persists

  24. My 2003 Ford Focus has 159k miles on it and had been running fine. I did go to a different gas station than usual, but nothing else I do changed. There were no warning signs or gradual changes, but I do know I need a new thermostat. Yesterday it just suddenly didn’t want to accelerate above 20-30mph, but sometimes suddenly would; the gas pedal felt stiff and I checked to ensure nothing was stuck underneath it. It felt like the gas pedal was suddenly looser when the car did pick up speed. I got an oil change today and they said no leaks, filters look fine…
    Your thoughts please?

    1. Why do you need a new thermostat?

      Could be a bad pedal assembly or an issue with the throttle cable (I think those still used a cable throttle, anyway).

      Does the gas pedal still feel stiff when the car is off? How do the throttle cables look in the engine bay?

  25. Hi, I recently got a throttle and brain box Mercedes Benz 203 replaced and I still have trouble accelerating, what could be the problem.

    1. Sounds like the problem may lie elsewhere, but it could be anything. You’ll need a professional diagnosis to narrow down the problem. Find a local shop you can bring your car into, pay a small amount for some diagnostic work, and they will help you figure it out.

  26. Just did maintenance work…. spark plug oil change and a valve cover gasket on a Nissan sentra 2.5l 2008. Now car will not rev over 2000 rpm or go over 5 mph… help!!!

    1. I have no idea. Check the basics: make sure your ignition coils are seated all the way on all the spark plugs, make sure spark plugs were torqued to spec, and make sure you didn’t forget to plug anything back in after the work was done.

  27. Hi. I have a 2007 toyota corolla LE. The problem is whenever I get to an intersection it sometimes doesn’t accelerate when i try take off. Sometimes i have to press the breaks hard and accelerate quickly then it will move.However if it’s moving and I let go of the accelerator when I do press accelerator it picks up immediately. Hasn’t really lost any power. This only happens when i stop and try taking off.

    1. Not sure, it could be any number of things. Is the check engine light on, and do you have any stored codes? When was the last time the spark plugs were changed?

  28. Hi. I have a 2015 automatic Honda Brio. The problem is whenever I get to an intersection it sometimes doesn’t accelerate when i try take off. Sometimes i have to press the breaks hard and accelerate quickly then it will move.However if it’s moving and I let go of the accelerator when I do press accelerator it picks up immediately. Hasn’t really lost any power. This only happens when i stop and try taking off.

    1. I’m not sure. Sounds like it may be a transmission issue that’s causing it to struggle when launching from a standstill, but it would be best to have it inspected so you have a better idea of what the problem is.

  29. 2011 toyota camry base 365k miles. All original stuff. Had a few times doing tune up, the usual tune up stuff like oil change, spark plug changing and that’s it. A sealed trannie and was told it was lifetime and no need to change trannie oil. I went ahead and did a drain and flush just last week. Took 2.5 quarts out only. Going to do a coil pack and spark plug this weekend. Last tune up was at 40k miles ago.

    Symptoms: Lack of power and when gear shifted 3 and 4, it vibrates for a bit. Drives ok to 65 and 70 mph on the highway ok but I have hills here in northern california. It can only go 50 mph and I’m not pushing it either. At first, I pushed it to 60mph and it rattles while rpm is at 2000 and it goes up and down, up and down with the rattling vibration, similar to the 3rd and 4th gear problem.

    This is the reason why I thought it was the trannie so I did a drain and fill and still no help. Just the other day, I changed the air filter and performance was a little better, the knocking on 3rd and 4th was lesser or maybe I went easy on the acceleration cuz I don’t want for the knock to be too hard on the trannie while in gear switching. I’m fixing it on the least amount of money first and go from there. The next step if changing out the coil and plug is to change the fuel filter. I did added them fuel system cleaner into my gas tank, in hoping to clear out the fuel injector if it is clogged. All these were done just recently and like I said, I got a gifted car that I drove like a race car, daily commuter to work 2 hours each way and passing cars and what not. I don’t even take care of it, just the basic changing out the engine oil every 7K miles on fully synthetic oil.

    i hope changing out the coil and plug will solve my problem and will continue to ride her till the next problem pops up. I need her to last till 2022 for me so I can replace her with a brand new vehicle. Thanks for the article, it was a big help in understanding the lack of power to the car.

    1. Glad the article helped you out. Was the problem there before you changed the transmission fluid? After the fluid change, did you check to make sure the transmission fluid level was correct? Do you experience the problem in every gear, or just 3rd and 4th?

      1. Well you know, like any other person who just pump gas and drive their vehicle without doing any major maintenance cuz you know, if it is not broken then why fix it. Problem came from pumping chevron gas station at a station somewhere up there in the high elevation mountain. My car first taste of different fuel additive from chevron. 3rd and 4th gear vibrates while shifting gears and usually at 2000 rpm is when it shifted. Then 5th to 6th gear seems ok driving hwy speed of 65 and 70mph. Uphill is when it lacks the power like it is still stuck in 6th gear with rpm at 1500. The drain and fill was done by the toyota dealership so I’m sure they did a good job at giving me proper fill. I mean I know how to do it too by using an ir gun to level out the oil method. I only went to the dealership cuz they do a courtesy X points inspection and gave me a list of results. Air filter was on there, I already did that and it was dirty. Fuel filter was on there so I’m definitely gonna take care of it next. I have not done a smoke test to see if there is any air leak. Thank you sean for that article I read. The dealership paper work did not list any plug or coil but since my car is old and when I did the spark plug change, one of the coil is red/orange oxidized coloration so perhaps that one is the bad one. Since my car is old with high mileage, I might as well change all 4 with 4 new plugs to complete the set. Was gonna do the fuel pump with the fuel filter but after the $1000 quote, I’ll just do the fuel filter for $200. I think these parts are in my fuel tank so I’m not gonna do it myself. No check engine light so my odb 2 reader shows nothing. What indicator I noticed about a month ago was the alternator light goes blinking. After that driving session, it stopped showing.

        At 366k, I only did 4 tune ups with the basic plugs, air filter, oil change and that’s it. oil change with synthetic and filter every 7,000 miles. Everything else is total neglect on my part but at the toyota dealership, when they did the x points inspection, looks like they topped off my fluids. Power steering, brake fluids, engine oil. Payed $200 bux though but it is better than giving it to them lube place where they hire kids to do their services at $170.

        Like I said before, I’m working on what is affordable to fix first and go on from there. I think I remembered you saying that sean and it pays to read your articles. I think it is the fuel pump is the culprit but at $800, I’m still debating if I should fix and ride her for another 100k or just buy another vehicle but I kind of wanting to drive her till 2022 when my hybrid truck comes out and I’ll just buy that new ride instead. For the time being, I just need to care for her just enough so she can last till next year. There are other components that can also be a factor like o2 sensor but usually with that, my check engine light would of gone off by now and the odb reader will pick that up. Hopefully I can find a solution so that others may find it helpful and they too can solve their own car problems. Thanks for everything so far Sean.

        1. Gotta give an update so others may learn to solve their own problems. I remembered when I was doing the coil and plugs, I disconnected the battery terminal so when it was done, the car started but can not idle. I then did the relearning system because the ECU need to remember the new set of plugs and will remember the new idle. A day goes by, idle bad again. Starts up fine but no idle. Went and got me two bottles, an MAF cleaner and a throttle body cleaner. Cleaned them both out for the very first time in 10 years and 366k miles later. Well what do you know? It started up just fine and even driving gave me a little bit more horsepower at the stop and go. However, driving up the hill is still a struggle. Still no check engine light so I can not pull any coding. Oh and once you clean out your throttle body, the check engine light goes on but them codes are for the MAF. I cleared it with my odb. Now with going up the hill not having the horsepower, it could be the fuel pump. My car has no fuel filter but perhaps it is embedded with the fuel pump. Well the fuel pump has a sensor right? If it goes bad, my check engine light would go on and say something like low pressure. No light. Plus if fuel pump is out, I wouldn’t be able to start the engine and while driving, it would die right? Not happen yet (knock on wood). So I’m thinking it is the trannie. Shift solenoid perhaps. I can go flat 65 to 75mph ok but once up that hill, I don’t hear a gear change and mph drops to 50. I know if I push harder to get a switch, my rpm would jump up and down at the 2000 rpm and the car will shakes like hell. This lead me to think that the gear was at 6th while driving flat and when up them hills, it got stuck and can not downshift.

          I’m at the crossroad of paying the mechanic his diagnostic fees to know for sure and fixing it will cost me a hefty penny. Perhaps I’ll just use that 2011 camry for non mountain driving and city driving only and take that money and buy another car because I do need another reliable car for the daily commute of 2 hours each way and 2 high mountains. I’m not too sure if I should bring it to a mechanic or a trannie specialist. Without a code, I just don’t know.

        2. If you know a good local mechanic, I would bring the car to him and pay the small diagnostic fee. It’s well worth it if he knows what he’s doing, it’ll save you both time and money in the long run.

        3. 2011 camry 367k miles, all stock and only tune up (plug, air filter, oil change) were done regularly. Already cleaned throttle body and maf sensor and had trannie drain and filled. Everything else is on borrowed time (starter, alternator, fuel filter, fuel pump, shift selinoid, cat converter, fuel injector… ect. ect.

          Took her to a local mechanic shop. Gave descriptions of what is the causal. 3rd and 4th gear has hesitation when changing gears. Up hill climbing can only do 50mph. ONce over the hill or on the flat, can do 65 to 70mph or more like normal to keep up with traffic.

          So the mechanic guy took the car for a joy ride. I saw him did that much. When he returned, he lifted my car up to see the bottom. Not too sure what he did to test or not test since I left the scene and came back 1 hour later. Pricing was $90 for diagnostic. So the results came back. I can not believe it but he said everything that I already thought I knew. His sheet of paper to fill out the report was empty. Could not repeat the problem since no check engine light was on. I’m like, you don’t need the check engine light to diagnose the air, fire or gas issues. I don’t have the equipment to test it thus why I’m bringing it to the professional in the first place. He then said he can not make recommendation or playing guessing game and have the customer getting mad when the problem still persist. Maybe they are just toying with me just to make a buck. I dunno.

          Maybe it is my fault for not asking what is a diagnostic and perhaps I can use what I learned from sean and explain it to them that I do know something about cars and don’t take me on for a joy ride.

          I then added another bottle of engine treatment cleaner and I’m getting better performance on the stop and go. The hesitation on 3rd and 4th gear is unnoticeable or maybe it is the way I drive as I am taking it easy with my car now. As soon as I hear the transmission on 3rd and 4th engages, I lay off the gas and doing so will not cause a shifting hesitation. I also do know that there are other potential problems like a bad cat which can show symptoms that mirrors a bad trannie. If I have a bad cat, I would have a hard time starting the car or have a max speed of lets say 40mph and/or the check engine light would go on with code p0420. Air not flowing out the tail end which pushes back the air into the engine to causes an overheat issue with the radiator or blown head gasket.

          My next step is probably gonna be taking my car to a muffler place and ask if they can check if enough air is coming out of my cat and if I needed a new cat, I will buy one from them. Free diagnostic right?

          If problem still exist, trannie shop here I come and maybe they can see if the torque convertor or shift selinoid needs to be replace.

  30. Hi Grayson –
    I have 2009 Altima and have experienced same issue. I’ve taken it to mechanic – nothing found. I’m afraid to drive it.

    1. KH, Grayson’s description left a lot to interpretation, and it will take a bit of troubleshooting to find the cause of both issues. They may even be different issues. I suggest you bring your vehicle to a different local mechanic and pay a small amount for a diagnostic service to help you find the problem. Ask around and see if you can figure out which shop does the best diagnostics.

      Alternatively you can try searching Altima forums to see if there is a common resolution for this type of issue.

  31. 2009 Nissan Altima with 125k miles
    After constant driving (an hour and half solid), the car will not accelerate when given gas. The RPM’s will not rev as more gas is given either. Only happens when car is taken on a small road trip. Transmission was replaced over a year ago.

    1. You’ll have to do some diagnostic work to narrow down the problem, it could be anything. If you are not comfortable doing that you will probably have to bring it to a mechanic to get the issue fixed.

  32. Hi, I recently got a throttle replaced and I still have trouble accelerating, what could be the problem.

    1. Do you have any more information about the vehicle, such as year, make, and model? Any peculiar noises or check engine light?

  33. hello.this is also the prblm of my car.so hard to reach 80 to 100kph.maybe i need to bring the car to the shop to avoid more problem

  34. Hi, my car Honda accord 2007 189k miles. Recently, the car can’t accelerate after stopping at the intersection. At that moment, the normal light and several other lights appear on the dashboard but the engine doesn’t run at all. I press the pedal but there is no sound, like completely shut down already but still has light. When I shut down the car and start the engine again, the car works normally. Is this cause by the alternator or anything else. Hope to get help from experts from you guys. Thank you!

      1. Al the lights like when I first turn the key ignited, but then I shut down the car and start it again, it worked like normal so I’m not sure if a part of my car failing or not. I heard that could be caused by the alternator. Have you heard about this situation happening on old cars?

        1. When you first turn the key, it’s normal for all lights to illuminate. This is a systems check to let you know that all lamps are working as expected. Is this what you’re referring to?

        2. Did you ever get your issue resolved? My 09 Murano is doing the exact same thing

        3. An altenator thats bad wouldnt allow you to just stop and turn off the car and crank it back up if the altenator were bad it would drain the power in the battery till its completely draines of power. The altenator is meant to recharge the battery if it isnt working like it should it will damage the cell in your battery after charging in over and over. So if you feel your having and altenator problem and want to save money grab a multimeter and go put the black to ground on battery and red to positive side of altenator and see if it has 12 volts or better going to it. Or just have it tested at your local parts dealer. You can pull it off if not able to move the vehicle and take it to them to test it. Easier that way because they require the core in exchange so if not good you already have it off the car and ready for the new one to install. Keeps from making 2 unnecessary trips

        4. A bad alternator wouldn’t necessarily drain the battery. The battery would keep the vehicle running while the battery had power. Since nothing is charging the battery, the vehicle will die when the battery voltage drops too low to fire the spark plugs and run the ECU.

    1. My son ran the front tire off and when I cranked it up to leave it sounded bad and it would not run but 5miles per hour

  35. 2009 model, Mazda 3 car in UAE. After one hour running the car suddenly not taking speed and this happened twice in summer peak time. Mechanic checked and told no issue found.

    1. Same problem with my sunny 2005 , suddenly accelerator stops working and engine light pops up while driving but engine still running. To get accelerator work I use to run off and on the engine.

      1. My car is doing this exact same thing! I had it at a mechanic and they couldn’t find what was wrong with it, did you get your issue fixed? If so what was it?!

  36. Good day, my Toyota corolla 2004 with 200,000 plus mileage, check engine light is on, car will start and move fine without AC, whenever I put on the AC and step on the gas it slows to move, am suspecting my half and top engine. What to u think?

  37. I have Toyota Yaris 2016, due to sandy weather I tried to blow out all sand stuck on my machine compartments and also cleaned the air filter, but after a while of starting the engine then suddenly check engine came out on monitor and at the same time I cannot accelerate even the pedal already press down…

    1. Get that code scanned. Perhaps you knocked something loose like the MAF sensor connector, perhaps there’s a vacuum leak somewhere after the cleaning. The code from the check engine light will help you narrow it down.

    2. I have VW Golf4 petrol car and it has acceleration problem, Thank you for the advice and the suggestions am yet to apply and see what happens
      Thank you

  38. My 02 protege is throwing a po300 code I’ve done change everything fuel pump, plugs and coils , maf sensor, cam and crank sensor,injectors seam to be working fine. When I try to accelerate with it in park .it just spits and sputter and sounds like a diesel engine but if i hit gas pedal just right and hike the ram engine sounds great ,idle it dont

    1. Bossman that a misfire code but it could be many of things you need have a compression test done on your cylinders bc they can loose compression and cause random misfires

    2. This is a symptom of a vacuum leak. Because unmeasured air is entering the engine and the ECU is reading maf signal to control fuel delivery at the injectors you are having lean air/fuel mixture resulting in rough idling. When you press the accelerator pedal the throttle valve opens drawing more air into the engine the vacuum becomes insignificant and your engine runs better.

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