11 Reasons Why Your Car is Slow to Accelerate

Few things are as frustrating as sitting behind the wheel of your car and expecting a quick burst of acceleration when you hit the gas, only to feel the engine struggle and the car lazily crawl up to speed.

Whether you need to merge onto the highway, accelerate quickly through a busy intersection, or simply want to “spiritedly” drive away from a stop light, sluggish acceleration can make driving tense and eliminate that sense of command we want over our vehicles.

Here are the common reasons why your car may feel slow to accelerate and how to identify the root cause.

Top Causes of Your Car Not Accelerating Properly

When you can’t pick up speed fast enough, it doesn’t necessarily mean that your engine is bad. Poor acceleration is often symptomatic of underlying issues in the mechanisms responsible for your car’s movement.

Here’s are some possible culprits:

1) Oxygen Sensor Problem

bad oxygen sensor

The function of the oxygen sensor is to keep track of the car’s exhaust emissions and determine the amount of fuel that is needed in the internal combustion chamber by tracking the air to fuel ratio.

If the oxygen sensor were to malfunction, the wrong amount of fuel would get burned during the combustion process. This would create a rich fuel mixture, which would result in slow acceleration as you step on the gas pedal.

2) Air Flow Meter Problem

bad maf sensor

The air intake cleaner has an air flow meter attached to it. As air flows into the air intake cleaner, the air flow meter calculates the mass of the air and then relays this information to the engine control unit.

Once the ECU has this information, it knows how to calculate the proper mixture of air and fuel. If there is a problem with the air flow meter, then it will give the wrong information to the engine control unit. This will result in slow acceleration.

3) Bad Timing Belt

bad timing belt

The timing belt needs to be in excellent condition. If there is just one tooth on the belt that is worn out, then you may have acceleration problems as you’re driving.

If you don’t replace the timing belt when you’re supposed to, you could have entire teeth on the belt break off and go missing, or the timing belt could snap altogether. A snapped timing belt will leave you stranded. If your vehicle has an interference engine (where the valves can make contact with the pistons or other valves when improperly timed), you’ll have expensive engine damage if the belt breaks.

4) Dirty Fuel Filter

bad fuel filter

If your fuel filter is clogged up with dirt and debris, then it is not going to let fuel pass through it. That means the fuel can’t enter the engine, which means you won’t be able to accelerate properly when you step on the gas pedal. In this situation, you must simply replace your fuel filter.

5) Electronic Error


If the central computer (ECU) or electronic system that controls your vehicle is getting glitches or errors, then it could wrongly determine that excessive amounts of fumes are being generated by your vehicle. Because of this, the computer will limit your ability to accelerate.

6) Bad Throttle Position Sensor

bad throttle position sensor TPS

The throttle position sensor is what analyzes the opening angle of the throttle valve. Once it detects this information, the throttle position sensor sends it to the engine control unit.

If this sensor were to malfunction, the gas pedal would no longer be able to control the speed of the engine because the pedal controls the throttle valve.

7) Neutral Gear

manual transmission gears damaged

There are some drivers who can’t pick up speed in their cars because they accidentally change the gear to Neutral instead of Drive. Either that or they’ll accidentally change it to Neutral as they’re already driving.

Sometimes if the shift stick is easy to move, this can happen. If you drive with the car in Neutral, then your car will simply rev its engine and not accelerate at all.

8) Bad Spark Plugs

best spark plugs

In gasoline engines, spark plugs ignite the air fuel mixture to power your vehicle. If your spark plugs are worn out, the spark plug gap may be too great for the spark to consistently fire when it should. This could lead to misfires and reduced performance.

9) Bad Spark Plug Wires/Ignition Coils

bad ignition coils

Bad spark plug wires or ignition coils may exhibit similar symptoms to bad spark plugs. If the insulation on your spark plug wires is worn away, the electricity that should power the spark plug may take a shorter path, preventing the electricity from arcing across the spark plug gap like it’s supposed to.

10) Clogged Exhaust

symptoms of a bad catalytic converter

If you have a significant restriction in your exhaust, combustion gases will not be able to exit the tailpipe very quickly. This leads to a buildup of back pressure, which will eventually hinder the vehicle’s ability to make power. A clogged catalytic converter will exhibit these symptoms. 

If you think your exhaust is clogged, it is best to address the issue as soon as possible. Exhaust gases are very hot and could cause a fire if they are not expelled properly. 

11) Slipping Clutch


If your clutch is slipping, you won’t be able to accelerate quickly even if your engine is working perfectly. Clutches slip when they get old, but also when they’ve been contaminated with oil or grease.

If you have a rear main seal or transmission seal leak, the clutch, flywheel, or pressure plate friction surfaces may have been contaminated. 

Diagnosing the Problem

Before attempting to fix an acceleration issue, you’ll need to diagnose the specific mechanical problem. There are a few ways to help determine what is causing your car to be sluggish:

A. Pay Attention to Sounds and Sensations

Slipping transmission or a clutch not fully engaging can feel like the engine revving before the car speeds up. A worn clutch may squeal briefly as you accelerate.

Gear synchronization issues lead to grinding sounds during acceleration. These sensations inform you something is not right.

B. Notice Problems Accelerating or Shifting

If the car hesitates or shudders when trying to accelerate, that often indicates worn transmission components. Difficulty shifting gears can also signify transmission issues or clutch problems in manual vehicles.

Acceleration issues that happen at certain speeds or engine RPMs can point to a specific mechanical deficiency.

C. Check Engine Light

The check engine light illuminates when the vehicle’s computer detects issues. Retrieving the diagnostic trouble codes via a code reader can reveal details about acceleration problems tied to ignition, fuel injection, emissions, or transmission parts. This is key to zeroing in on the fault.

Paying attention to what you see, hear, and feel while accelerating can help narrow down problem areas. Diagnostic computer scans also assist with pinpointing issues to address. This saves you time and money on repairs.


65 thoughts on “11 Reasons Why Your Car is Slow to Accelerate”

  1. Just changed my Toyota Camry 1999 gear oil and filter because of slow acceleration and speedometer and odometer fading but it is coming on and off, though the speed is ok.

  2. Hi I have Hyundai Genesis coupe recently it have to where it slow down and I have to press on brake then gas to make it go faster again what could be the problem?

      • Our diesel engine 1050 hp truck problem is the speed is decrease on upwards movement with load we check fuel pump is working good give us our required revolution 2100 rpm after this we replaced new injectors but our problem can not be solve any one have idea about this

  3. Hi folks! I have a 2000 Ford Expedition. It was used when I bought it and engine light has always been on. I’ve taken it for checkups and the problem has always been the same O2 sensor. Now, I’m experiencing trouble accelerating. It can stay at 5 mph for a while, the 10-15 mph then it will get to regular speed unless I go up a hill. However, I can back up fine with no problems at all. Please help. By the way, thanks so very much for sharing this information.

  4. Hi guys, I have this issue in my diesel 2.0. however it only happens when its on idle around 800rpm and it takes ages to reach 2000rpm, after this, the car works as usual, but every time i have to lower revs, for example, 4th gear, slow drive, and push the pedal… its really bad to rev up also.
    After reaching 2000rpm everything is great, pulls like a train, good revs up to highway and play along.
    the car has no throttle sensor, no errors are displayed in dashboard or ecu.

  5. i have a 98 toyota camry with about 250,000 miles. the past 5 years the acceleration has gotten very weak. in general it’s weak and when i go up a steep hill, it only goes 20 miles. I know it is an old car, but i don’t think it becoming this weak is normal. Any thoughts on what it may be?

    • It could be a lot of things. When was the last time the spark plugs were changed? Air and fuel filters?

      Start with regular maintenance and if it still feels slow, go from there.

  6. Hi, I have Hyundai EON Era Plus car 2014 model manual transmission. Sometimes, when i shift from 3rd to 4th gear, accelerator is not working/ speed not increasing. It happens sometimes only. When the car is completely stopped and starting again from first gear helps. Again, this is not solve for all the times. Due to this, i am so open for accidents especially in busy road and slope driving’s. Kindly advise and help on this.

  7. Dear help me with a mysterious problem
    My wagon r is 2014 (k10 engine) , running on petrol no CNG fitment till now.

    Covered nearly : 82000kms

    It’s delivering mileage of 9/10 kmpl only. Calculated tank to tank. I always fill full tank instead of small amounts.

    I have noticed that On the highway with constant pedal pressed without moving even a bit , it loses very slight power for few kms and gets back to normal for few kms and this circle goes on……….

    The problem is there since the past 2 years.

    Got clutch plates and pressure plate changed twice so that it will help me get a normal mileage as I was getting few years back of 14/15 in city

    Throttle body cleaned multiple times,

    And what not

    Took it to Maruti suzuki authorized dealer and got the ECU checked too but there was no problem on that screen

    Really annoyed now

    Got it checked with multiple mechanics

    No one is able to figure out the exact problem

    All says there is no smell at exhaust, no such issue with pickup and no black smoke so as per them it’s something which God can only solve ?

  8. Hi, my car is not picking up acceleration on the initial moving or when I stop and go again. Once it picks up then there is no problem it is driving ok. What can be the possible problem? Will it cost my wallet???

  9. I have a Toyota Camry 1999 model. It doesn’t start quickly in the morning and cold weather and may even kill the battery. But it starts when in the afternoon sun. Above all whenever it starts it makes loud POP sounds and don’t accelerate well

    • It might be popping from running rich, I’m not sure. Is there a check engine light?

      Try cleaning your battery terminals if they are corroded. You might have a poor connection to the battery.

  10. Hi,

    I have a 2005 reg Toyota AVENSES diesel. Heard a pop under the bonnet whilst driving on side roads at 15 miles/hr. Car continued to drive but began lacking power when accelerating… And became slow to accelarate from 2nd and 3rd gear upwards even with the gas pedal is floored.
    On the motorway, it takes about 15 seconds to speed up 5 miles and takes a good 2 miles motorway driving to reach 65/70 miles/hr with the gas pedal floored.
    Oil and oil filter changer, air filter changed. A pipe had had broken in the engine which was repaired. Still experiencing issue of power loss. Any ideas what I should be looking at next apart from changing fuel filter?

    • My car, toyota camry 2.4 6cylinder car not picking up when slow down on motion and wanted to drive again pick up very slow

  11. Got a 1990 Volvo station wagon that’s getting pretty elderly, but still puttering along. Even putting the petal to the metal only gets a measly amount of acceleration. It’s fine once it’s going, but I’m worried about getting onto highways etc. what would you say is the most likely culprit?

    • It could be anything, honestly. Start with the simple stuff first, though. You can try replacing the spark plugs and plug wires, clean the throttle body, clean the MAF sensor if it has one, and change your engine air filter (yep, this can actually make a difference). Good luck on your search.

  12. My started behaving bad on hilly tops. I will not move on hilly tops unless I wait for it for ten minutes to move a gain. I changed the pump but problem still exist

  13. I have a 2009 Mitsubishi Pajero.
    Engine always runs slowly and some times goes off on applying the brake.
    Please what could be the cause.

    • This could be a problem with the mass airflow sensor. That item can disappoint you by making engine slow & causing it to shut off sometimes. I suggest full diagnosis of the vehicle to confirm the cause.

  14. Hi,
    I have a Kia Picanto 07 model,it accelerates normal when parked for days or used under less pressure. However, it starts to accelerate slowly when climbing hills and driving off in traffic when used continuously for hours. But with the AC on, the ignition goes off. What could be the cause?

  15. I have a Renault Sandero Stepway 2015 900T
    Vehicle has a whine while idling in the morning or when cold.
    Also, when driving, from 1000 revs to 2500 revs the car is sluggish in every gear.

    could it be the internal oil pump or the oil pressure as this were 2 opinions shared with me

  16. I use a Toyota Camry 2005 . I have poor acceleration of my car when climbing the hills and when it’s extremely sunny.
    The gear was checked and confirm to be working well.Kindly help with other possible factors.

  17. Hello I have a 2000 Toyota Tacoma sr5 v6 that when idle my steering wheel vibrates a lot my shift stick with move to neutral with a little bit of pressure forward and I have trouble getting up to speed unless I put my pedal to the floor and will then accelerate

    • I don’t know what’s wrong with my car if i throttle it, it take few seconds to accelerate and after accelerating when I remove my leg from the gas pedal then the rmp goes up itself then I have to hold my break and if I on my AC when on pack it goes off

  18. Hi so when i floor my car I don’t gain a lot of speed and my rpms don’t really go up that fast but when I left off a little bit I gain speed but not as fast as I want, would this be the torque converter or is it maybe my O2 sensor?

    • If your O2 sensor is bad you’ll usually have a check engine light. It’s probably not the torque converter, because it sounds like the transmission isn’t slipping based on your description. You’ll have to do a bit of diagnostic work to narrow down the problem.

  19. I have a 20 year old beat car, the pick up has come down added to that, there is a jerking when acceleration is increased after changing the gear. The local mechanic told that this could be the problem of the engine cylinder. Only three cylinders are working the 4th one needs to be checked? Is that right. Is there a relation between cylinders and acceleration?

    • Yes. An engine is designed to work with a certain number of cylinders. If one cylinder has little or no compression, the engine will likely feel sluggish and you will experience more vibration. The firing order of the cylinders is designed to help balance the engine and make it smooth, so when one cylinder isn’t contributing power the car won’t feel or run right.

  20. Looking for advice on a 2006 Mistubishi Galant 2.4l with an automatic transmission. It really struggles to pick up any speed. The rpm gauge is in sync with the speedometer and doesn’t jump up. It seems to be a little better if I start with L1, the L2, L3, then D. But only a little better. When I let it shift on its own it seems to be a smooth shift when it eventually builds up enough rpms. Catalytic converter was changed around 4 years ago. The problem started around a month ago and have gotten progressively worse. Any suggestions? Thanks!

  21. Hello. I have an 01 nissan
    Pathfinder. It has a very hars time getting up to speed and sometimes it backfires while speeding up. Also it accelerates all on its own when I’m going slow. It also has a hard time going up big hills. I have to speed in order to ger past a hill. Someone said it could be my spark plugs but after reading this it may be something else. Any ideas?

  22. I changed my fuel pump but my car stops running on slow motion. But when I start the engine back,it will start accepting again. It has happened several times. What could be responsible for that and what is the remedy? Thanks

  23. Hi. I have a fiat Punto Evo 2012. When go up the hill my speed drop to 40km/h in 3rd gear. The speed doesn’t increase and the acceleration pedal is completely down. I need some advice please

    • 40 kph is pretty slow to go up a hill in 3rd gear, especially with a smaller displacement motor. I used to have a Subaru WRX with nearly 300 hp, and even that car would struggle a bit under those conditions. Try dropping down to 2nd gear to see if it helps.

      If you think it’s more than just the gear ratios working against you, I’d ask some fellow owners on a forum to see if they have any advice.

  24. When I go to motorway my car had no problem but when I go to small gear some time not pick up like engine has no power.
    I did service last two we Ago all filter and oil changed don’t know what to do .
    Mechanic check with computer he said everything is ok just take your car on motorway to burn the diesel, I went through but still not very good.

  25. Hi, my car not picking up acceleration when I stop and going again once it pick up then no problem is going ok, I did service last week my car is diesel Bmw 2008 5 series and coming smoke also when i accelerator it I don’t know what to do now, car just slow down in 1 or 2 gear.

  26. My 3s start perfectly, and engine light goes off but takes longer to accelerate, diagnosis shows the car is OK but you have to press the pedel down to the end opening the throttle valve wide to Start picking up, and Some times the engine light blinks and gain power at the same time, any idea for this

    • A blinking check engine light often means the car is misfiring. I would do some troubleshooting to see why this is. Check the spark plugs and wires, replace if necessary. Look for other check engine lights that are stored in the computer. These will help you understand what’s causing the misfires.

  27. How do i know which one is my problem? When i go up a hill the car doesn’t pick up speed like i can’t get it above 60 mph and i press on the accelerator and the revs just keep going up quickly but the speed doesn’t go up. Wha could be the problem ?

    • This sounds like a slipping clutch or torque converter. This will likely be most noticeable in 3rd or 4th gear. If you have a manual transmission, a clutch replacement should fix the issue. For an automatic, further diagnosis is needed by a mechanic in your area.

      • Am experiencing exactly this issue as stated here I use automatic car, what could be the solution when it applies to automatic car.

      • Torque converters are used in place of clutches on automatic vehicles, so it’s possible you have a slipping torque converter. It’ll be hard to say for sure without a mechanic’s diagnosis though.

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