When your car jerks when accelerating, it can be an uneasy feeling and leaves you wondering if there’s anything wrong with the car. Cars are designed to run smoothly under almost any condition and for a long period of time. A car jerking or hesitating under acceleration could mean any number of problems, from a faulty spark plug to a transmission problem. We’ll discuss further what a jerking car feels like, what the possible causes are, and potential repair costs.
- Jerking Under Acceleration
- Causes And Repair Costs
- Jerking At Different Speeds
- Automatic Transmission Jerking
Car Jerking When Accelerating
Most cars will run smoothly with no problems over their lifetime, so it’s normal if you’re not sure what a car jerking during acceleration feels like. If you’re still unsure about what’s going on in your car, we’re here to help you understand what it actually feels like when this problem occurs.
A car jerking usually feels like the car is hesitating during acceleration, even under full throttle. Try putting your foot down and then pay attention to the rev counter. A healthy car should have its RPM climb up the rev counter smoothly with no problem.
If your car is jerking, then often the rev counter would stop climbing for a second or two, and then starts to climb again. Depending on the cause, your car might also backfire and you would hear a firing sound from your engine. Often it will repeat this process several times during acceleration.
This video below might give you an idea of what it feels like when a car jerks when accelerating:
Needless to say, if your car jerks when accelerating, it can be unsafe to drive. The reason is that if you’re accelerating from a full stop, it can be difficult for you to gain any speed. And if your car is already moving and you have this problem, then maintaining speed can be difficult.
When a car has this problem, it’s often engine or drivetrain related, so your check engine light might come on as well. It would be wise to take your car to a mechanic as soon as possible and get the problem solved. Driving with this problem can be dangerous, as it would be difficult for you to control your car’s speed.
Why Does My Car Shake When I Accelerate
Before we get into the possible causes of this problem, we’d like to note that you might be the problem. Yes, you. Okay, what we mean is that if you’re driving a stick shift and it’s your first time driving it, or maybe you haven’t driven a stick shift in a long time, your gear change may be the issue here.
Your gear shifting might not be as smooth as the car needs it to be, causing the car to jerk as you shift gears and drive along. You should learn more about how to drive a stick-shift properly if you think your driving might be the issue.
However, if you’re sure in your driving skills or your car is automatic, there are several common causes for car jerking. Keep in mind that these are only a few, and your car’s problem might not be included in the following list:
1. Dirty Fuel Injectors
This is one of the most common issues for why a car jerks when accelerating. Fuel injectors are supposed to provide a steady stream of fuel into your cylinders. A dirty fuel injector would be unable to do this, and your engine won’t get enough fuel to burn. As a result, your engine won’t work properly and your car will jerk under acceleration. It can also often misfire as you try to accelerate.
A dirty fuel injector won’t need to be replaced and you can simply clean them instead. Most repair shops will charge you between $50 – $100 to clean it, and it should take no more than a couple of hours. You can also clean your fuel injectors yourself to save money, the most basic cleaning method simply requires you to add a cleaning fluid into a nearly empty fuel tank. Other methods will require tools and basic mechanical knowledge to do it.
2. Bad Fuel Pump Or Fuel Filter
Fuel supply issues are often the cause of a car jerking when accelerating. Other than dirty fuel injectors, your car might have a bad fuel pump or fuel filter. A bad fuel pump won’t be able to pump the correct amount of fuel into the engine. While a dirty fuel filter will clog the system, again causing the incorrect amount of fuel to be fed into your engine.
Fuel pumps vary from one car to another, and replacement costs will vary depending on your car’s make and model. The average cost for a fuel pump replacement is around $450 but can vary between $250 – $1000. You will need to visit a repair shop for a more accurate estimate. Meanwhile, a fuel filter typically costs no more than $165 to replace, including labor.
3. Damaged Fuel Lines
Most cars will have a metal line that runs underneath the car that connects the fuel tank to the engine. If you have a damaged fuel line, then it might lose pressure. This in turn causes a loss of pressure in the fuel line and your car is able to feed the appropriate amount of fuel into your engine.
If there’s damage or a leak on your fuel line, then you will need to replace it. A simple replacement job should cost no more than $120. However, if your car requires your mechanic to drop the car’s fuel tank to replace the line, then it could cost you upwards of $500 as more effort is needed to replace the fuel line. Look out for a puddle of fluid underneath your car when parked to see if you have a fuel leak.
4. Faulty Spark Plugs
Your engine’s spark plugs are responsible for igniting the fuel and air mixture inside your engine’s cylinders. This starts the combustion process and powers your car. When a spark plug goes bad, it won’t be able to ignite properly as the spark will be too weak or it might not even spark at all.
As a result, your engine won’t run smoothly and cause engine misfires. Most spark plugs will need to be changed between 20,000 – 30,000 miles. They’re usually part of routine service and are changed regularly by your mechanic. So if you maintain your car properly, it shouldn’t be a problem.
If your spark plugs go bad prematurely, then you might want to give your engine a full check as something else might be causing it. In any case, bad spark plugs will need to be replaced. The total cost is usually around $20 – $150, but you can replace them yourselves as they’re quite simple and there are lots of video tutorials online. The spark plugs themselves usually cost no more than $20 each to buy. You can save a bit of money by doing it yourself.
5. Moisture In Distributor Cap
Much like the spark plug, the distributor is an essential part of your car’s ignition system. If your car has a distributor-type ignition coil, then moisture can build up inside its cap, causing the ignition coil to be unable to send high voltage electricity to your spark plugs correctly. This often happens when you live in a snowy area or during the winter and you’ve parked your car outside for too long, causing moisture to build up.
Most modern cars will have a coil-on-plug system, meaning the ignition coil sits directly on top of the spark plugs. In which case, you can rule out this possibility as the coil-on-plug system doesn’t have a distributor cap. If you do have a distributor-type, there’s no need to replace it.
You can learn more about ignition systems in the video below:
6. Blocked Air Intake Or Faulty Mass Airflow Sensor
Your car takes in the air outside using an air intake, which it then uses to mix with fuel and ignite using the spark plugs. A blocked air intake or faulty air sensor will make the car unable to suck in the air it needs. As a result, the combustion process won’t run smoothly, causing your car to jerk as you try to accelerate it.
The repair cost will vary for a blocked air intake depending on the severity of the problem. For example, if it’s caused by just a dirty air filter, then replacing it should cost around $80 – $150. However, if an entire replacement of the intake system is needed then it would cost $500 on average. Keep in mind that this would depend on your make and model, and some cars can cost upwards of $1000.
Meanwhile, a faulty mass airflow sensor can cost anywhere between $250 – $400 to replace. The mass air flow sensor helps your Engine Control Unit (ECU) in balancing the fuel amount it feeds into the engine. A faulty mass air flow sensor will cause the incorrect amount of fuel to be fed into your engine.
7. Worn-Out Accelerator Cable
A worn-out accelerator cable can cause your car to experience acceleration problems. This cable sits between your gas pedal and the throttle plate in your engine. When you press the pedal, it will open up the throttle plate and allows more fuel to be fed in, making you go faster. The cable can wear out over time and disrupt the accelerating process. It’s also possible that there’s slack on your accelerator cable, causing the throttle to work improperly.
You should check the cable immediately and replace it if necessary. If the cable breaks then your car will cease to work completely. Most accelerator cables will cost you no more than $150 to replace including labor costs. Keep in mind that with some cars the cost may go upwards of $350.
8. Clogged Catalytic Converter
The catalytic converter is part of the exhaust system and it’s responsible for reducing the emission that your car produces. Most catalytic converters will last for 10 years before it needs to be replaced. However, your car’s mileage and engine tune may affect this.
Also, if your catalytic converter fails prematurely, it’s often caused by a more serious issue in your car. Possible causes include faulty fuel injectors, an ignition coil, and a blown head gasket. You should watch out for colored smoke coming out of your exhaust, which indicates a serious issue with your car and may cause damage to your catalytic converter.
If the catalytic converter is clogged or damaged, it allows exhaust gas to build up in your car, causing the car to jerk when accelerating. Your car might even stall as you try to accelerate. A catalytic converter replacement cost is anywhere between $900 – $2500 depending on your car’s make and model.
9. Bad Transmission Control Module
When a car jerks when accelerating, it can also be caused by a transmission problem. A common cause would be the transmission control module, often called the solenoid. This module is responsible for gear changes as you drive along. If you have a bad control module, you’ll notice your car will have a bit of lag as it tries to change gear. In severe cases, the car will jerk violently when changing gears.
As with most car parts, the replacement cost for a transmission control module varies between cars. You can expect to pay between $500 – $900 when replacing the control module.
10. Defective Carburetors
The carburetor is responsible for controlling how much fuel and air are being mixed before it is fed into the engine. If the carburetor is damaged, then it won’t be able to do this properly and will lead to your car misfiring and jerking under acceleration. If your car was made after 1995, you can gloss over this. Carburetors have fallen out of popularity since the ’90s since fuel injectors are far more reliable.
However, if you have an older car with carburetors, then a car jerking during acceleration can be caused by a bad carburetor. Sometimes all your car needs is a good service, which will typically cost between $200 – $300. But if your carburetor has gone bad and needs to be replaced, then you should expect to pay between $500 – $800.
Most of the issues mentioned above will cause your check engine light to come on. If it does, we advise that you take your car to a repair shop and fix the problem. If your check engine light is flashing, then you should stop driving immediately as it indicates that there is a serious issue with your car.
Car Jerks When Accelerating At Different Speeds
As you can see from the list above, several potential issues can cause your car to jerk when accelerating. You can narrow down the possible causes of your car jerking by paying attention to at what speed your car jerk. Different issues can cause your car to jerk at different speeds. Meaning if your car jerks at slow speeds, the problem that causes it can be different from when a car jerks at high speeds.
Car Jerks When Accelerating At Low Speeds
When a car jerks at slow speeds, there are a variety of problems that could cause it. However, it’s often attributed to faulty spark plugs, which aren’t too complicated to deal with. A replacement job or a quick tune-up should resolve the issue quickly, and they aren’t expensive to do.
Keep in mind that it can also be caused by air intake, catalytic converter, or fuel injector and carburetor problems if you’re in an older car. If changing or servicing the spark plugs doesn’t help, then you will need to check the other parts.
Car Jerks When Accelerating At High Speeds
Airflow issues are often the cause when a car jerks when accelerating at high speeds. Your car needs more air to take into the engine at high speeds. If there’s an issue with your intake system, then your car will struggle to feed the engine with the correct amount of air. As a result, the combustion process will be disrupted and your engine can’t run properly. Which causes misfires and your car jerking as it tries to accelerate.
You should have your air intake system and mass air flow sensor checked if you experience this and have it replaced if necessary. But other problems may be causing this as well.
In any case, it would be best to check your car immediately if you’re experiencing this. A car that jerks during acceleration at high speeds can be dangerous to drive, as you might lose control of your car’s speed. Your car might lose its speed rapidly and you could be rear-ended by drivers behind you if they’re not aware.
Car Jerks While Driving At Constant Speed
If you’re trying to accelerate from a full stop or while moving at a constant speed and your car jerks, your car is telling you that it’s not getting the fuel it needs to accelerate smoothly. This is often caused by dirty fuel injectors or fuel pump issues, where the fuel system isn’t able to provide a steady stream of fuel into your engine. This can be stressful as it means your car will struggle to pull away even in the most common driving conditions such as pulling out of a parking space.
Automatic Transmission Car Jerks When Accelerating
As we’ve said, if you drive a manual then the acceleration jerks might be caused by improper gear change. If you have an automatic, your car may jerk because of transmission problems but it’s not as common. Fuel and air supply issues are the most common causes of a car that jerks when accelerating.
The next common issue is with the ignition system, where your engine isn’t igniting the fuel and air mixture properly. Both problems affect the combustion process and often cause misfires that result in the car jerking as it accelerates.
Compared to engine problems, a transmission jerk is usually more distinct. Your car usually jerks as it tries to change gear, or it would hesitate or take longer to change gear. If you experience this, then the most common problem will be with its solenoid.
If you believe that you’re experiencing transmission issues, it would be best to visit a repair shop and diagnose the problem. A bad transmission is very dangerous to drive with and it can fail at any time. You can learn more about transmission symptoms in the video below:
The cost for a transmission repair job will vary from one car to another. However, severe damage to the transmission is quite costly to fix. You’d typically need upwards of $4,500 to rebuild or replace a transmission.
Can I Drive A Car That Jerks When Accelerating
You can, but we would advise against it. Depending on the severity of the issue, you might still be able to drive the car with minimum interruptions. However, it would be wise to diagnose the problem and fix it right away. As we’ve said, the problem may affect your control of the car and put you in danger. Most of the issues that cause this will turn on the check engine light anyway, which means you really should fix your car.
A car jerking during acceleration can be an uneasy and worrying feeling. The good news is that you can easily avoid this by following the required service routine and maintaining your car properly. Most of the parts that cause misfires are often serviced or replaced during maintenance. Therefore, proper maintenance can help you to avoid acceleration jerking problems.
That being said, jerking under acceleration can be caused by more serious issues such as transmission and catalytic converter problems. Whether it’s because the parts are nearing their lifespan or something else is causing premature damage, we strongly advise you to fix these issues as they are very serious.
If the repair costs are too expensive, then another option is to sell or scrap your car. If you wish to proceed with the repairs, find out if other problems caused the parts to fail prematurely. Leaving it unfixed will keep causing damage to other components in your car.
Whatever the cause is, be sure to follow your car’s service schedule and repair the problems as necessary. A car that runs smoothly is not only more comfortable to drive, but also safer.
FAQs On Car Jerks When Accelerating
If you’re still puzzled by why your car jerks when accelerating, perhaps our FAQs here might help…
Why Does My Car Jerk When I Accelerate
There are several reasons why your car jerks when accelerating. The most common of which can be attributed to fuel not being able to flow into the combustion chamber. Thus, it won’t let the engine ignite and run properly. This includes dirty fuel injectors, bad fuel pumps, clogged fuel filters, or damaged fuel lines. All of which can prevent fuel from circulating to the engine. Besides that, it could also be a failure of your engine to ignite the combustion mixture correctly. We can blame bad spark plugs, moisture in your distributor caps, or there might be something amiss in the ignition and throttle system. A blocked air intake or faulty MAF sensor would also cause your car to jerk while it’s accelerating. Elsewhere, we might also blame the catalytic converter or even the transmission.
Why Is My Car Jerking When I Give It Gas
In addition to jerking under acceleration, your car might also exhibit issues where it’s jerking and shaking as you’re giving it the gas from a full stop. This would include a jerky sensation anytime you’re maneuvering at low speeds like trying to park or are pulling away from a junction. Usually, situations like these mean that your engine isn’t able to get enough fuel. Most of the time, dirty fuel injectors may clog the flow of fuel into the engine. Otherwise, a bad fuel pump or clogged fuel filter may also prevent fuel from being able to flow freely into the engine. While you’re there, it’s also worth checking the fuel lines to ensure that there aren’t any obstructions.
What Does It Mean When Your Car Jerks While Driving
One of the easiest ways to tell if your car is jerking while driving is to pay attention to the tachometer. Press your foot against the gas pedal, and observe how the rev counter’s needle moves. If your car is working fine, that needle should smoothly and gradually climb its way up the RPMs. However, if you notice the needle pausing and stop climbing for a second or two, then it’s a sign that your car is jerking while driving. Another way to notice if your car is jerking while driving is to pay close attention to how your car feels. Acceleration should mostly feel progressive and smooth. If you notice any hesitation from the car to move, even after you’ve stomped on the gas pedal, that’s another tell-tale sign that your car is jerking while driving.
Why Does My Car Jerk When I Brake
When you’re braking, your car should scrub off speed and slow down to a halt gradually and smoothly. In other words, it shouldn’t jerk, shake, or vibrate noticeably. If you can feel this happening, the most common underlying issue would be something going wrong with your brakes. Typically, this would mean that you’re most likely braking atop a set of worn-out brake pads or brake rotors. Both of which need to be replaced urgently. In addition, there could also be something wrong with your brake fluid, such as a lack of fluids in the reservoir. Or, the presence of air bubbles inside the brake fluid. Faults with the ABS (anti-lock brakes) could also cause your car to jerk under braking. As is other random problems cropping up elsewhere in the braking system.
Why Does My RPM Go Up And Down While Parked
When your car is parked up and is basically left idling, the RPM should remain steady. Anytime you’re noticing the RPM needle bouncing up and down, there’s usually something wrong with the engine. The most common point of failure is the presence of vacuum leaks. Alternatively, perhaps your engine’s idle air control (IAC) valve isn’t functioning right. Otherwise, we can look towards problems with the EGR (exhaust gas recirculation) system, bad O2 (oxygen) sensors, faulty throttle position sensors, or a worn-out MAF (mass air flow) sensor. Aside from that, we may also blame the spark plugs, fuel injectors, or fuel pump that’s causing your engine’s idle to fluctuate.
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