Your drive can be unfulfilled or ruined when your car jerks as you accelerate. It is embarrassing for other motorists to think you do not know how to drive properly, but it can also mean you may be facing some expensive repairs if you do not figure it out soon.
Let’s discuss some of the common causes of your car jerking or lurching and what you can do about it.
Reasons Why Your Car is Jerking, Lurching, or Stuttering When You Accelerate
When you feel like your car is jerking, surging, bucking, or stuttering when you step on the gas pedal, you know something is amiss.
You may feel your vehicle becoming sluggish when accelerating, or feel it jerk or jump when letting off the accelerator.
There can be several reasons for this, ranging from dirty fuel injectors, worn spark plugs, a clogged air filter, a bad mass airflow sensor, a blocked catalytic converter, a failing fuel pump, transmission issues, to damaged acceleration cables.
There are likely other things that could be causing your car not to accelerate properly. You want to identify and fix the issue quickly so that it doesn’t become worse, which could lead to higher costs for repairs.
#1. Dirty Fuel Injectors.
This is a common and annoying issue. You have probably seen dirty injectors for a number of reasons, as when it comes to dirty injectors, your car can lose power and be jerky from a stop or driving at a constant speed due to intermittent engine misfires. A good indicator here is that the car engine makes an audible stutter from the inconsistent fuel intake.
Cleaning of the car’s fuel injectors should be done regularly to avoid the buildup of the injectors. Most of the time, fixing the issue can be fairly simple using a good injector or fuel system cleaner.
However, it could be the case that the injectors foul up so badly with carbon deposits that even the best injector cleaner won’t solve the issue. In this case, you will either need to remove the injectors to try and manually clean them, or just replace them entirely.
#2. Blocked Fuel Lines.
There could also be a block to the fuel lines, which is interrupting the flow of fuel required for your car to accelerate.
The air combines with the fuel to create a mist that equates to your engine’s combustion. If this process is interrupted in any way, this could really affect your acceleration in the car.
#3. Worn-Out Spark Plugs.
One of the easiest to identify and repair is that the combustion of fuel could not properly occur due to a good spark being present when needed. The spark plugs often become damaged, like a bad or dirty spark plug, and the misfire occurs.
While driving, you notice the vehicle jerks or shakes when you accelerate. The loose insert is just to replace the bad plug. If you can’t remember when you last changed your spark plugs, it might be better to change them all out, as this is an easy, inexpensive fix.
#4. Dirty Air Filters.
As you move through your reading of this article, you will realize that improper air/fuel mixture is often the common issue, as your car does not have anything from sputtering out or jerking without accelerating.
Opposite the fuel side of things is proper air intake. When too little air makes it into the combustion chamber, you’ll often feel the same effects as with too little fuel. The air filters serve as the first barrier against dirt and any number of foreign particles.
A dirty air filter allows a number of particles to get to your engine, which then can hurt performance and cause jerking.
Check the air filter for dirt. If the filter is dirty, it will need replacing. It is a $10-$20 item and will only take a few minutes to replace. Alternatively, you can purchase a reusable air filter, such as a K&N, so it will allow future cleanings in place of replacement.
A clean filter can improve engine life expectancy substantially, decrease and/or eliminate the acceleration jerks. Your engine will last longer with clean filters.
#5. Damaged Cylinders.
If your engine cylinders have been damaged, this will hurt your engine’s ability to work properly and cause an engine misfire. If this is the case, you will want to inform your mechanic, as they can fix the cylinders, or you could quickly ruin your engine.
#6. Blocked Catalytic Converters.
The job of the catalytic converter is to cut down on the number of pollutants that leave a car through the exhaust. If the air/fuel mixture in your engine is too rich, you can develop blockages in a catalytic converter over time that will block air flow through the exhaust system.
Thus, you may have stuttering, jerking, and delayed response when stepping on the gas pedal. Besides jerking, you might have other symptoms including a rotten egg odor (hydrogen sulphide), a substantial diminished in your gas mileage, and the check engine light may light up.
You may also be able to clear small blockages by first trying a good catalytic converter cleaner. But if that doesn’t work, it’ll most likely be the repair shop for you, and expect to pay to replace the catalytic converter.
#7. Clogged Fuel Lines.
When fuel lines are clogged, it is usually a result of dirt, debris, or contaminants in the fuel itself creating a restriction to the fuel flow to the engine. Clogged fuel lines can cause the car to jerk when you accelerate, especially at a constant speed.
Dirty fuel filters, fouled fuel injectors, and the use of low-quality fuel often cause clogged fuel lines. And just for clarification…yes, if someone pours sugar (or some other foreign substance) in your gas tank, clogged fuel lines will be the least of your worries.
#8. Broken Acceleration Cables.
Another item might be a broken acceleration cable. Acceleration cables are the link from the gas cable to the engine throttle plate.
Thus, when you press down the gas pedal, it pulls the throttle open, and chances are your car accelerates as demanded.
#9. Broken Carburetors.
A carburetor mixes air and fuel before it reaches the engine. Consequently, a broken carburetor not only causes the car to jerk when accelerating but will reduces performance in general.
#10. Moisture in the Distributor Cap.
If it happens to be snowing outside when your car wants to hesitates and jerks when you accelerate, that could be a result of moisture in the distributor cap, which usually happens in the wintertime if your car is parked outside.
Parking in a warmer area would “hopefully” limit the possibility of this happening.
#11. Faulty Mass Airflow Sensor.
When you feel your car jerking or surging at highway speeds, it may be the result of a mass airflow sensor (MAF) that is failing. The mass airflow sensor measures air intake to relay its information to the car’s computer.
From the data provided by the MAF, the engine computer tells fuel injectors when and how much fuel is to be injected to achieve the desired air/fuel mixture.
If the mass airflow sensor is suspect, you may notice that you get those unexpected jerks or surges, particularly at highway speeds, where you can notice it.
There should be a check engine light if the mass airflow is bad, but easily verified with an OBD2 scanner.
#12. Bad Fuel Pump or Filter.
A cause of the car jerking when accelerating is usually a fuel supply problem. Most of the time, if the correct amount of fuel is not supplied to the engine, feed this back to the beginning.
In this case, the car’s fuel pump. A faulty, failing fuel pump would have trouble keeping up with the demand for fuel, ultimately causing the car to jerk or surge forward while driving.
A clogged fuel filter could also be a cause for restricting the flow of fuel, while not enough fuel is provided, the engine performance would be all over the place.
Changing out the fuel filter can be an easy and inexpensive process.
#13. Engine Control Unit (ECU) Problems.
The Engine Control Unit (ECU) is like the “brain” of the vehicle – it controls everything about how the engine works. If your ECU is having issues, it can cause poor engine performance or a lurching motion when pressing into accelerator.
An ECU problem usually shows up in the form of warning lights on the dashboard, loss of power to the engine, or hesitation in accelerating.
To diagnose the ECU problems, an automotive technician can plug in an OBD scanner and retrieve any stored error codes. They would also check for any performance issues, check for any physical damage, and check wiring and circuits.
If necessary, the ECU can be reset, updated, or replaced completely, then calibrated, to resolve ECU faults and drive or travel smoothly.
#14. Transmission Problems.
The transmission system will cause the car to lurch during acceleration, especially if you have an automatic transmission vehicle. This problem will arise if the transmission fluid is low, broken, or contains any internal damage that will affect the gear shift process.
You should check your transmission fluid and replace it every 50,000 to 60,000 miles or so, to ensure the transmission is working well.
Regardless of whether you are changing the fluid or going through a repair or replacement, addressing this problem will keep your transmission system in the best shape possible to help accelerate your vehicle smoothly.
#15. Throttle Position Sensor Problems.
The throttle position sensor will relay the position of the gas pedal to the computer. In some way, this also helps with acceleration. If the throttle position sensor is damaged, it can cause erratic acceleration or jerking when pressing on accelerator.
The throttle position sensor may need calibration or replacement to help relay the best throttle position and avoid interruption in acceleration.
Signs that the throttle position sensor is not functioning correctly include poor performance of your engine, hesitation when accelerating, or a general inability to hold a steady speed.
If you suspect throttle position sensor problems, it is recommended that you have it checked and serviced professionally so that your vehicle’s throttle system can be, once again, operating correctly.
When you take it to the mechanic, they will read the car’s onboard computer that stores error codes. They will visually inspect the throttle position sensor to check for any physical damage. They will clean the throttle position sensor and the connectors and adjust the throttle position sensor alignment.
Check Engine Light vs No Check Engine Light
When the Check Engine Light Is On
When your vehicle jerks and the check engine light is on, there is an issue that needs your attention. The problems causing your vehicle to jerk could likely be:
To determine what the exact problem you are having is, simply have your vehicle scanned with an OBD2 Scanner, which will indicate what the problem is based on the code. Once you have this code, you now have the information needed to start the repair process.
When There Is No Check Engine Light
If your vehicle jerks while accelerating and there is NO check engine light on, it is not the time to panic, but it IS NOT a good sign either and cannot be ignored. When the CEL does not turn on, here are the affiliates:
- A blocked or dirty air filter
- Low transmission fluid
- Clogged catalytic converter
In this situation, if your vehicle has a blocked or dirty air filter, it is best to check the air filter and replace it as necessary. Make sure you check your transmission fluid level.
Most importantly, you should check with a qualified mechanic regarding the different sensors and catalytic converter, which could be causing your jerking issue even though it has not caused the CEL to engage.
Maintenance and Repair
Tune-up
In order to avoid having your car jerk or stutter while driving, you should perform a wait of maintenance inspection or at least a tune-up periodically.
Tune-up procedures usually consist of checking for gaps and or replacing spark plugs while checking ignition coils, replacing filters, inspecting sensors, checking wiring and locations for proper functionality, and a variety of other areas directly involved in power train maintenance and repair.
You can get away with poor quality maintenance, however, these maintenance areas can work on your vehicle performance before these components become a significant issue.
Fuel Injector Cleaner
To ensure your fuel injectors are clean, use high-quality fuel injector cleaner every few thousand miles. This prevents unwanted buildup and ensures your engine is getting an optimal mixture of air and fuel to accelerate normally.
To use fuel injector cleaner, just follow the directions of the product and pour cleaner into your gas tank during your fill-up.
Catalytic Converter Cleaner
A clogged catalytic converter can contribute to your Car jerking or hesitating while accelerating. You can first try using a catalytic converter cleaner or fuel system cleaner to remove deposits obstructing it from working properly.
Auto Repair Shop
If you have tried everything you can think of and can’t find out what is making your car jerk while accelerating, you should try visiting an auto repair shop.
They often have training and/or the diagnostic tools, equipment, and experience to pinpoint your vehicle problem and perform repairs as necessary.