Nothing ruins your drive like a car that jerks when accelerating. Not only is it embarrassing as other motorists think you don’t know how to drive, it can mean you may be looking at expensive repairs if you don’t get it figured out soon.
Let’s look at some of the most common causes of a jerking or lurching car and what you need to do to get it fixed.
Why Your Car Jerks, Lurches, or Stutters When You Accelerate
When car feels like it’s jerking, surging, bucking, or stuttering after you step on the gas pedal, you know that something is off.
Your vehicle may also feel like it’s dragging something when you accelerate or even jerk or jump when releasing the accelerator.
It could be due to several issues including: dirty fuel injectors, worn spark plugs, a clogged air filter, a faulty mass airflow sensor, a blocked catalytic converter, a failing fuel pump, transmission problems, or damaged acceleration cables.
However, there are other things that can be the cause. You want to find and fix the problem as soon as possible before it gets worse and becomes more costly to fix.
#1. Dirty Fuel Injectors.
This is a common and annoying problem that can be responsible for a variety of issues. Dirty injectors can cause your car to lose power and make your car jerk while driving at a constant speed or from a stop due to frequent engine misfires. You can also hear as the engine stutters from inconsistent fuel intake
Cleaning the injectors should be done regularly to avoid this problem. Thankfully, this process is quite easy using a fuel injector or fuel system cleaner.
However, the injectors can be so fouled up with carbon deposits that even the best fuel injector cleaner may not do the trick. In those cases, you’ll have to either have to take the injectors out to attempt to manually clean or simply replace them.
#2. Fuel Blockages.
There might be a blockage that is preventing your car from receiving the fuel it needs to accelerate. The air mixes with fuel to create a spray that powers your engine. If anything interrupts this, your car might struggle to accelerate.
#3. Worn Out Spark Plugs.
One of the most common causes is also one of the easiest to identify and fix. During the combustion process, a good spark is needed to properly ignite the fuel in each cylinder.
A bad or dirty spark plug can prevent this proper ignition and will cause the engine to misfire. While driving, it feels like your vehicle jerks or shutter when accelerating.
Fixing this problem is as easy as replacing the bad plug. If you don’t remember the last time you replaced your spark plugs, it may be a good idea to get them all changed out. This is a quick and inexpensive repair.
#4. Dirty Air Filters.
As you read this article, you’ll notice an improper air/fuel mixture is often the culprit if your car jerks or sputters when accelerating. Opposite the fuel side of things, is proper air intake.
When not enough air makes it into the combustion chamber, you’ll often get the same issues when not enough fuel.
Your car’s air filter is the first line of defense against dirt and other foreign particles. A dirty air filter will allow some particles to get into the engine, which in turn will affect performance and cause jerking.
Check the condition of your air filter. If it’s dirty, replace it. It should only cost $10-$20 and take a few minutes to replace. Alternatively, you can purchase a reusable air filter such as a K&N which allows for future cleanings instead of replacement.
A clean filter can drastically improve the lifespan of your car’s engine, including reducing or eliminating the acceleration jerks.
#5. Damaged Cylinders.
If your engine cylinders are damaged, this will affect the ability of your engine to work properly and will lead to an engine misfire. You will want to notify a mechanic of this issue so that the cylinders can be repaired or replaced. Otherwise, you can quickly ruin your engine.
#6. Blocked Catalytic Converters.
A catalytic converter is responsible for reducing the amount of pollutants that exit out of a car’s exhaust. When the air/fuel mixture in your engine is too rich, a blockage can develop in the catalytic converter over time which disrupts the airflow of the exhaust system.
This can result in stuttering, jerking, and an overall delay in responsiveness whenever you step on the gas. Besides the jerking, other symptoms may include a rotten egg odor (hydrogen sulphide), a drop in the car’s fuel efficiency, and the check engine light may come on.
You may be able to unclog minor blockages by first using a good catalytic converter cleaner. If that doesn’t work, you’ll need to take it to an auto repair shop to fix the problem which will likely include replacement of the catalytic converter.
#7. Clogged Fuel Lines
When your fuel lines become clogged, it’s often due to a buildup of dirt, debris, or contaminants in the fuel itself. As a result, the fuel flow to your engine becomes restricted, causing your car to jerk when accelerating, especially at constant speeds.
Often, a dirty fuel filter, fouled up fuel injectors, and the use of low-quality fuel are to blame. And in case you’re wondering, yes, if someone pours sugar (or another foreign substance) in your gas tank, clogged fuel lines will be only the beginning.
#8. Damaged Acceleration Cables.
The acceleration cable might be damaged. This cable is the link between your gas cable and the engine throttle plate. Pressing the gas pedal causes the cable to pull the throttle open, allowing your car to accelerate.
#9. Defective Carburetors.
The carburetor is responsible for controlling how much fuel and air are mixed together before it enters the engine. When the carburetor is damaged, this will not only cause your car to jerk when accelerating but will also lead to poor performance in general.
#10. Moisture on the Distributor Cap.
If it’s snowy outside, your car might hesitate and jerk when accelerating due to moisture accumulating on the distributor cap. This typically occurs during the winter when you park your car outside. This can be avoided by parking your car in a warmer spot.
#11. Faulty Mass Airflow Sensor.
If you notice your car surging forward or jerking at high speeds, it may be due to a mass airflow sensor (MAF) that is failing. Its job is to measure the amount of air entering the engine so it can relay this info to the car’s computer.
The computer then instructs the fuel injectors to provide the right amount of fuel at the right time for proper air/fuel mixture.
With a faulty MAF sensor, you may experience your car unexpectedly jerking or surging forward while driving at higher speeds such as on the highway where it would be most noticeable.
A check engine light should be present when the mass airflow sensor is bad but you can easily confirm via an OBD2 scanner.
#12. Bad Fuel Pump or Filter.
The cause of your car jerking while accelerating is often a fuel supply issue. When the correct amount of fuel is not being delivered to the engine, it’s often best to start at the beginning.
In this case it would be the car’s fuel pump. A failing fuel pump would struggle to keep up with fuel demands and cause your car to jerk or surge forward while driving.
Alternatively, you may have a clogged fuel filter that’s restricting the flow of fuel which also can cause issues as fuel delivery is inconsistent. Replacing the fuel filter is a fairly simple and inexpensive process.
#13. Engine Control Unit (ECU) Problems.
The Engine Control Unit (ECU) acts like the vehicle’s brain, controlling various aspects of engine operation. If the ECU malfunctions, it can lead to poor engine performance and lurching during acceleration. ECU issues are typically characterized by warning lights on the dashboard, reduced power, and hesitation during acceleration.
Diagnosing ECU issues involves using an OBD scanner for error codes, checking for performance problems, inspecting for physical damage, and circuit testing. If necessary, resetting, updating, or replacing the ECU, followed by calibration, can resolve these issues and promote a smoother driving experience.
#14. Transmission Issues.
The transmission system can cause car lurches during acceleration, particularly in automatic vehicles. This issue may arise if the transmission fluid is low, contaminated, or has internal deterioration, affecting the smoothness of gear shifting.
Inspect and change your transmission fluid every 50,000 to 60,000 miles to keep the transmission working well. Whether changing the fluid, making repairs, or getting a replacement, addressing transmission issues will keep your transmission in optimal condition and ensure your car accelerates smoothly.
#15. Throttle Position Sensor Issues.
The throttle position sensor communicates the gas pedal’s position to the car’s computer, influencing acceleration. A faulty sensor can cause irregular acceleration and jerking. Calibration or replacement of the throttle position sensor is necessary to ensure accurate communication and smooth acceleration.
Signs of a malfunctioning throttle position sensor include poor engine performance, hesitation during acceleration, or difficulty maintaining a consistent speed. Professionally inspecting and fixing sensor issues ensures optimal performance of your vehicle’s throttle system.
Your mechanic will check the car’s onboard computer for error codes. They’ll also visually inspect the sensor for damage. Then, clean the sensor and its connectors and adjust its alignment.
Check Engine Light vs No Check Engine Light
When the Check Engine Light Is On
When your car jerks and the check engine light is on, it’s a clear indication that there is a problem needing attention. In this case, the most likely issues could be:
- Dirty or clogged fuel injectors
- Worn-out spark plugs
- Bad O2 Sensor
- Fuel pump malfunction
To diagnose the issue, you should get your car scanned with an OBD2 scanner, which will help you identify the specific problem causing the check engine light to come on. Based on the code retrieved, you can take the necessary steps to fix the problem.
When There Is No Check Engine Light
If your car jerks while accelerating and there’s no check engine light, you don’t need to panic, but don’t ignore it either. When the CEL is not illuminated, here are the :
- A blocked or dirty air filter
- Low transmission fluid
- Clogged catalytic converter
In this case, it’s advisable to first check the air filter and replace it if necessary and then check your transmission fluid level. Also, have a mechanic check the various sensors and the catalytic converter as these could be causing the jerking issue without triggering the check engine light.
Maintenance and Repair
Tune-up
To prevent your car from jerking or stuttering while driving, consider performing regular tune-ups. This includes replacing spark plugs, checking ignition coils, and inspecting other essential components like sensors and filters. A routine tune-up can help address performance issues before they lead to more severe problems.
Fuel Injector Cleaner
Keep your fuel injectors clean by using a high-quality fuel injector cleaner every few thousand miles. This prevents buildup and ensures that your engine receives an optimal fuel and air mixture for smooth acceleration.
Simply follow the product’s instructions and pour the cleaner into your gas tank during a fill-up.
Catalytic Converter Cleaner
A clogged catalytic converter can cause your car to jerk or hesitate when accelerating. Use a catalytic converter cleaner or fuel system cleaner to remove deposits and restore proper function.
Auto Repair Shop
If you’re unable to diagnose or resolve the issue causing your car to jerk when accelerating, consult a professional at an auto repair shop. They have the expertise and equipment to identify the root of the problem and perform the necessary repairs.