While driving, you go to accelerate, and your car jerks. Whether the jerking is accompanied by another symptom or alone, the vehicle is trying to say something. It is best to drive to safety and find the source of the jerking.
Here we will examine why the car jerks while accelerating the solution and its possible cost.
Car jerks when accelerating: Possible reasons and solutions
1. Spark plugs
Engine misfiring is caused by spark plugs that are worn out. Fouled and worn spark plugs interrupt the perfectly timed fuel ignition in the cylinders, creating the jerking you experience.
Replace the spark plugs is the easiest and least expensive solution. For $20, any DIYer can do this quick fix!
2. Clogged fuel injectors
Gas goes through the fuel injector to get to the engine. Dirt that accumulates in the fuel injectors reduces the amount of gas that is traveling through the injectors and causes jerking on acceleration.
The easiest way to keep the fuel injectors clean is to add a bottle of fuel injector cleaner to a full gas tank and let it clean the fuel injectors as you drive.
Suppose you still have a problem with jerking when accelerating after using the fuel injector cleaner.
In that case, it could be carbon buildup that must be removed by manually cleaning the fuel injectors, which most mechanics will do for no more than $100.
3. Carburetor issues
The carburetor is responsible for balancing the fuel/air ratio.
When the ratio is compromised, you will feel jerking on acceleration and hear the engine misfire. You will notice that your engine performance is reduced as well.
This is only a problem in cars before 1995 that had a carburetor when manufacturers replaced the carburetor with fuel injectors.
A tune-up by a mechanic or tuning it yourself is the solution. If the problem remains, you must replace the carburetor at $650 to $850.
4. Acceleration cable damage
The accelerator cable is the braided metal cable that runs from the throttle plate to the gas pedal.
As you step on the brake, the cable opens the throttle. Its position under the car leaves it open to corrosion and wear and tear.
Once the line fails to open the throttle, your safety is compromised.
A damaged accelerator cable is a serious issue. Replacing the acceleration cable is not a DIY fix.
A new accelerator cable will cost about $175 to $450. A reputable mechanic should do this to ensure it is done correctly.
5. Fuel line clogs
It’s no secret that the perfect air/fuel mix is essential for a smooth-running engine, so any interference in the ratio will change the engine’s performance.
Any blockage in the fuel lines will change the combustion timing in the cylinders if your spark plugs ignite the wrong air/fuel ratio.
The jerking – as you accelerate – will be accompanied by the check engine light coming on. This is the worst-case scenario that could cause an engine fire!
Examine the gas line for damage. If you suspect a clog in the gas line, change the gas line. It isn’t costly and much cheaper than replacing the engine damage, especially if it leads to a fire!
This fix is a “good news and bad news” replacement. If the fuel line is easily accessed, it will be cheaper at $90 to $120. But if the gas tank has to be dropped to get to the line, you are looking at more than $550.
6. Air intake clogs
The air intake pulls outside air into the car to be used for the fuel/air ratio—too much air or not enough air into the mix changes the spark plug’s spark.
You will experience jerking on acceleration along with the check engine light being lit.
Since the air filter is the first line of defense, if it is clogged by dirt or debris, that air can’t pass through it. Replace the air filter first, as it is a cheap replacement at $80 to $150, and see if the jerking improves.
If there is no improvement or the check engine light remains lit, you should check for a faulty mass airflow sensor.
7. Bad mass airflow sensor
The mass airflow sensor registers the quantity of air entering the engine, letting the vehicle’s computer know to initiate the proper air/fuel ratio to keep the engine running at its optimum.
You will notice this most often as you drive at a higher speed rate and feel the car surging, especially if you do a lot of highway driving.
The defective mass airflow sensor will set off the check engine light.
A defective mass airflow sensor is a bit harder to detect, but a code scanner will give you the diagnosis code, so you will know whether it is the mass airflow sensor or something else.
The airflow sensor can cost between $250 to $400. Once you have the code, you can change the mass air sensor or fix the diagnosed issue.
8. Moist distributor cap
Parking outside, especially in cool, wet weather, can cause your distributor cap to build moisture.
The moisture only impairs the ignition coil in cars with distributor coil ignition because it impedes the current to the spark plugs. Once the coil dries, the issue resolves itself.
Since the jerking stops when the ignition coil dries, preventing the moisture is the fix. Parking in a dry garage or carport with a moisture-preventing thermal cover ($40 to $50) should do the trick.
9. Faulty cylinders
Your cylinders regulate compression and piston speed. Both are vital to the engine.
Defective cylinders can result in jerking on acceleration, but they also cause the engine to misfire, leading to bigger problems, including breakdowns.
Faulty cylinders need repairing or replacing immediately. The damage caused by them is expensive. This extensive repair should be done by a professional.
The cost is anywhere from $300 to $700 unless the head is cracked, which can cost up to $1000.
10. Catalytic Converter clogs
If an air/fuel ratio is too rich (too much gas, not enough air), it can clog the catalytic converter. The catalytic converter monitors your car emissions.
Once the catalytic converter is blocked, you will get a sulfur smell like rotten eggs accompanied by the check engine light, jerking and possibly stuttering as you depress the accelerator.
Eventually, you will see poorer fuel performance too.
Since replacing a catalytic converter will set you back between $1200 to $1400, use a catalytic converter cleaner first.
The cleaners are relatively inexpensive and definitely worth a try. If that doesn’t solve the problem, you will have to have it looked at by a mechanic.
11. Faulty Fuel Filter
Most acceleration problems have to do with poor fuel supply—a clogged fuel filter results in little to no fuel getting to the engine. The intermittent fuel supply is responsible for the jerking as you accelerate.
Replacing your fuel filter is the best option. This cheap fix you can do yourself for $25 to $90.
12. Defective fuel pump
Fuel pumps pump fuel, so no gas will be pumped if the fuel pump is bad. The lack of gas will affect acceleration and cause jerking.
Fuel pump replacement is the only solution. Those mechanically inclined can replace it for the cost of the part. Depending on the car, a professional replacement can cost $400 to $500.
13. Transmission selenoid issues
In an automatic transmission or car that gear shifts, when the selenoid (transmission control module) is faulty, you will feel the shifting delay in the form of a jerk.
While it isn’t very common, it is worth looking into if all the above have been fixed and you are still jerking as you accelerate. Fixing this issue will cost between $500 to $1000.
Three things you can do to prevent jerking
Stop revving the engine
Revving the engine, especially at higher speeds, is not good for the motor.
Don’t change cylinder heads
There’s a reason the manufacturer used the cylinders they did. Leave this up to a mechanic when and if it is needed.
Skip the racing
You accelerate consistently as you drive. Why put extra pressure on the system by accelerating to higher than usual speeds? The engine doesn’t need the excess strain.