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car jerking when pressing gas pedal

Why Does My Car Jerk When Accelerating

A car that jerks or is hesitant upon acceleration is more than likely having issues with combustion from within the engine. In short, the reason a car will jerk under acceleration is due to:

  • Blocked Catalyst
  • Faulty Spark Plugs
  • Defective Acceleration Cable
  • Dirty Fuel Injectors, Filter or Hoses
  • Poor Electrical Voltage
  • Engine Tuning Flat Spot

To get an idea of the symptoms of car a car that is hesitant under acceleration, we discuss these in more detail. To fix hesitant acceleration, the first protocol should be to give your car a full service that will knock off the majority of the above symptoms.

Clogged Catalyst Causing Hesitant Acceleration

A blocked or clogged catalytic converter will be more common in older cars from the year 1990 on wards. The purpose of one is simply for emission control but they do cause issues from time to time. if you went to a garage, they will put your car onto a diagnostic machine to locate the problem.

To a clever test to see if you have a blocked catalyst is to remove the oxygen sensor. If the car accelerates properly without issue, you may have located your problem. Other symptoms of a blocked catalyst include poor fuel economy, hard starting, poor emission and an engine management light.

The hesitation when acceleration with a blocked catalytic converter is because the exhaust gases can’t pass through the muffler. You can solve this by using the best catalytic converter cleaner you can get your hands on to clean the system.

Bad Spark Plugs Cause Poor Acceleration

Gasoline cars require a good spark in order to ignite fuel for internal combustion. As part of a medium to major service, they should be changed with the recommended spark plugs for your car. Failure to provide your engine with the best possible spark has consequences such as:

  • Engine Misfire
  • Poor Fuel Economy
  • Hesitant To Accelerate
  • Hard To Start
  • Poor Exhaust Emissions

If you know that your car has not had its spark plugs replaced in a while, for the small cost, get them changed.

Damaged Accelerator Cable Causing Jerking

The accelerator cable will go through much more use than other vehicle components. Although a simple piece of engineering, as a car ages, so does the cable. It can become damaged under extended uses that can cause a delay when putting your foot down on the accelerator pedal.

Do not carry on driving the car daily until you have fixed the problem. The cable is giving you a nudge to say that it will break and you will be stranded with no accelerator functionality.

Hesitant Acceleration Due To Fuel Supply

The main components to a vehicles fuel system are the injectors, pump, filter, hoses, tank and more.

If a vehicle is struggling to get enough fuel, the car will jerk when accelerating. Always begin replacing the easiest and cheapest part first, which is the fuel filter.

The next step would be to ensure that the fuel injectors are as clean as possible. To do this, fill your car with the highest octane fuel and for a diesel car use a diesel fuel additive and for gasoline cars, I strongly recommend using Chevron as a cleaner. This will also ensure that all the fuel hoses/line are clean and fuel is not getting blocked.

Bad Voltage Causing Jerky Acceleration

Weak electrical power can play havoc with any car because most fuel pumps require a voltage. If the voltage is too low, not enough fuel will be pumped around the car. Electrics in a car can be diagnosed with top rated automotive multimeters to give accurate readings.

Most common culprits will be the alternator or an old battery that needs replacing. Bad voltage will most probably be the last thing you will think of with regards to the acceleration being jerky but it does happen.

Poor Engine Tuning Causes Hesitant Acceleration

If you have tried replacing all the common parts and still no avail, the issue may be with the ECU. Tuning your car with a remap is common but if done incorrectly, you may cause issues with acceleration such as jerking.

Take your car back to garage that tuned your car and ask them to diagnose the issue.

procarreviews author

Written By Dan

About the Author

Dan is an automotive journalist and owner of over 10 cars ranging from supercars, tuned cars, classics and your good old beater cars. He always like to get his hands dirty with nut and bolt restorations or detailing sessions using the best products on the market.

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What Are Your Thoughts?

  1. Dear,
    I have Mistubishi Lancer 1.6litr automatic transmission model 2006, my car start normally, accelerate normally , gear shifting is normal, even Rpm is normal at all stages, but when I reach at speed of 40km or above the car start lossing power while I start pressing pedal more it become normal, am facing this issue since a week please reply me

  2. My 1986 mustang when driving will suddenly drop 100 rpms and jolt from the deceleration, it happens more when it’s cold than when it’s warm and it jolts harder at lower rpms, It started having this problem when I replaced the starter relay, the starter relay also welded its inner plates together so the starter stayed on after it was started, I tapped on the relay with a wrench and the problem stopped. I’m thinking that either my engine is misfiring or the relay is arcing causing the starter to engage and slow down the engine.

  3. Hi,I’ve filled up the tank in my KB280 tdi,now experiencing a jerking problem after a couple of days,especially when accelerating faster,when letting go of the accelerator it switches of. I’ve cleaned all pipes thinking of blockages but problem persists. Help!!

  4. Hi

    I have a battery that i know need to be replaced and i am experiencing some jerking. But this only happens when the car is still cold and when i pull away in first gear. When i go uphill and the car is cold the problem becomes worse.

    In this article it talks about bad voltage, but i only get the problem when the car is still cold. When i drive a few kilometers (about 5 km) the issue goes away. Can it be that the voltage on start up is not strong enough and why would it worsen uphill?

  5. hi im driving opel astra does bad hydrolic lifters or valves cause the car to jerk and loose power..?

  6. I am having polo highline 2010 model. From few day my car is jerking lot. I showed mechanic, but mechanic is telling he can’t getting any problem.(he checked all parts of car, but stil he can’t getting what I’d the problem.) What is the car.. Please tel me

  7. Many newer computer controlled cars will not allow acceleration if the foot brake sensor is actuated. This new safety feature causes people who are left foot brake operators, or heel toe drivers, to confuse the vehicle’s on board computer since they tend to drive with their left foot touching the brake pedal. If the brake pedal is touched during acceleration this will cause the engine not to accelerate, hence there is staggering, stalling, and poor engine performance. If a left foot braking drive, or a heel toe driver does this enough times, depending on the vehicle, it can cause the computer to become confused and the engine will have ongoing stalling or acceleration problems. I have a friend who owns a new Ford F150 who is also a left foot brake operator. Ford diagnosed his driving habits using a secondary on board computer. The secondary computer recorded events where the brake sensor was being actuated during acceleration. This was happening because his left foot was sometimes touching the brake pedal in conjunction with acceleration..If you are having this problem, notify your auto service mechanic and he may be able to reset the computer to prevent this. However it will return if you don’t change your braking habits, because sooner or later you will touch that brake pedal while under acceleration..Note! keep both feet away from touching the brake pedal during acceleration. No more heel acceleration and toe on the brake to take off on a hill either..For obvious reasons this problem caused by heel and toe, or left foot braking drivers, is not widely publicized by the makers of these vehicles who have this on board computer controlled safety system. Just great isn’t it? A safety system that ruins a vehicles performance and even creates driving hazards…No wonder most vehicle manufacturers are not quick to admit this problem even exists..

  8. I just put new plugs, new thermostat and new valve cover gasket on my car. Now my car is spitting and jerking when driving. Throwing 1 code but it’s the temperature gauge sensor which has nothing to do with that. Can you please help.

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