10 Reasons for Car Jerking When Accelerating & How To Fix It
It is no fun driving a vehicle that is jerking, losing power, then surging and acting erratically. As your vehicle jerks, it also distracts drivers from their main activity, which is driving safely and avoiding accidents. Severe jerks can cause additional damage to the car’s engine, the transmission, and other parts of the drive train.
Losing power on the highway can cause dangerous situations to develop, causing accidents. Our car engines have become very complex. Manufacturers have made many changes to the engines and the transmissions to squeeze as much fuel economy out of them as possible.
Governments have mandated significant reductions in emissions to reduce smog and improve the air we breathe. Most car engines come equipped with Engine Control Modules, which are computers that run our vehicles.
They rely on many different sensors on the engine, the transmission, and even the exhaust to deliver optimum fuel economy. Based on these inputs, they control fuel injection, spark ignition, and airflow to manage the combustion process and the power delivered to the transmission.
Any time these components malfunction, the combustion of the air-fuel mixture is compromised, and your car performs poorly and may even deliver a jerky, surging, stuttering ride. When the car starts jerking or if your car jerks when accelerating, have it checked by a mechanic at an auto repair shop.
10 Causes Why Your Car Jerks When Accelerating
We expect our vehicles to accelerate smoothly until it reaches the desired constant speed. If the car hesitates while accelerating while under full throttle, many people describe it as a jerking feeling or sensation. When a car engine hesitates, the RPM level stops climbing, as does the speed increase.
The episode may last one or two seconds before resuming full power and accelerating the vehicle. There are multiple potential causes for this type of situation to occur. In some cases, the engine may also backfire and may repeatedly backfire several times while continuing to accelerate.
Lack of acceleration can present dangerous conditions, especially if you are entering a high-speed highway. If the car loses power at the wrong time, another vehicle may crash into you because they were expecting you to continue accelerating at the same rate instead of hesitating.
Have your vehicle’s engine check immediately and review some of the reasons that may be causing this situation.
#1 Dirty fuel injectors
Fuel injectors can be compromised over time due to carbon deposits that build up. A dirty fuel injector does not release fuel properly. The fuel is supposed to spray into the cylinder and then shut off. A spark is generated by the sparkplug, and combustion pushes against the piston to turn the crankshaft.
A fuel supply issue reduces the amount of combustion and power generated. Since there is less power, your car may suddenly stop accelerating. The engine can backfire as well, making a loud noise that is easily heard from inside your car.
Fuel injectors can be cleaned by purchasing fuel injector cleaner and adding it to the gasoline. Following the instructions to gain the maximum benefit. If adding fuel injector cleaner does not work, you may have to make arrangements for the injectors to be removed for cleaning or replacement.
#2 Clogged catalytic converter
Catalytic converters are installed on all modern vehicles to reduce the pollutants exiting the car’s exhaust system. If the air-fuel mixture is too rich, carbon deposits can build up inside the catalytic converter and disrupt the flow of air and exhaust gases through the converter and exhaust system. This can even result in a blocked catalytic converter.
As airflow through the system declines, the air-fuel mixture suffers, and there is less power generated during combustion. There may be a delay in responsiveness, especially when accelerating. This is commonly described as jerking.
In addition, there may be a rotten egg smell and a drop in the fuel economy of the vehicle. Airflow is monitored through a system of sensors and reported to the Engine Control Module. In a situation where there is poor airflow, poor fuel efficiency, and the check engine light may be illuminated.
A catalytic converter cleaner can be utilized to clean the converter. However, if this does not work, the converter may need to be replaced. Drivers should also have their engines tuned up to ensure that the engine is properly optimized.
#3 Faulty mass airflow sensor
The mass airflow sensor counts the quantity of air entering the engine through the air intake system. The ECM of your vehicle uses this information to control the amount of fuel injected into the cylinder for combustion. As more air enters the engine, more fuel can be injected to increase the power produced by the engine.
If a faulty mass airflow sensor is reporting incorrect information to the ECM, either too much fuel or too little fuel will be injected into combustion cylinders, causing surging in some cases and hesitation in others.
Drivers may observe this as jerkiness while driving at high speeds on the highway. In addition to driver distraction which can be dangerous, if the car suddenly loses power, vehicles following you may have to swerve into another lane to avoid your slowing car.
The check engine light should illuminate, which can easily be confirmed to be the mass airflow sensor, by attaching a code reader to read the error code indicating the mass airflow sensor is failing or has failed. The mass airflow sensor may also indicate a blocked air intake due to a dirty air filter.
#4 Bad transmission control module
The transmission control module or TCM manages the transmission to ensure that it is synchronized with the engine and changes gears to match the load and speed as needed. The Engine Control Module or ECM manages the operation of the engine.
In many vehicles, this function is combined into one module called the power train control module or PCM. A faulty TCM or PCM can cause significant changes in the way the transmission operates. If gear shifts are delayed or become unpredictable as you accelerate the TCM, or one of the solenoids operating in the transmission could be at fault.
If these conditions are harsh or jerky, the TCM could be the common point of failure. A jerky car or failure to change gears can be distracting while driving and place you in a dangerous situation on the highway or even lose control. Check the error codes reported and include the TCM in your efforts to troubleshoot the problem.
#5 Blown head gasket
A blown head gasket can also be the indirect cause of a car being jerky while accelerating. The blown head gasket prevents oil from mixing with the engine coolant and prevents air from entering or leaving the combustion chamber other than through the valve assembly.
Drivers may not notice a bad head gasket until their catalytic converter becomes clogged, potentially causing poor engine performance and even jerky operation. Older catalytic converters that are clogged should be changed. When they become clogged prematurely, indicate other problems with your car’s engine.
Poor air-fuel mixtures caused by bad injectors, mass airflow devices, faulty spark plugs can also cause this problem. Add a faulty head gasket to the list of issues that can also contribute to poor air-fuel mixtures, which can also contribute to a plugged catalytic converter.
Listen to the engine while it is idling. If you notice a hissing sound, there is a good chance the head gasket is blown. Have the engine serviced immediately to avoid additional serious damage to the engine.
#6 Bad spark plugs
Bad spark plugs or worn-out spark plugs or wires can cause your engine to misfire, feeling like a stutter or jerky feeling while you are driving. The spark plug provides the spark that ignites the air-fuel mixture during combustion.
The fuel must be ignited at the correct time inside the cylinder with a strong spark. Failure to provide a spark or intermittent spark can cause a host of problems for your engine. Check the maintenance recommendations for your engine.
Most manufacturers recommend when your plugs should be replaced to ensure continued optimum engine performance. Replacing all the plugs and the spark plug wires is relatively inexpensive. Replace all of them at the same time to avoid additional maintenance issues later on.
Poorly combusted air-fuel mixtures caused by bad spark plugs can also contribute to a build-up of carbon around valves and exhaust systems.
#7 Dirty fuel filter
A car’s engine relies on the correct mix of air and fuel entering the combustion chamber. Anytime this mixture is not optimum, an engine’s performance is compromised. Dirty fuel filters reduce the flow of fuel along fuel lines to the fuel pump and the engine.
At times the engine may be starved of fuel and then suddenly receive sufficient fuel leading to surging and jerking of the vehicle as the engine generates the power demanded by the driver.
Replacing a blocked fuel filter is inexpensive and should cost no more than $10 to $20, plus labor. While the filter is being replaced, the fuel pump should be checked at the same time to confirm it is operating properly.
Dirty fuel filters can occur whenever fuel tanks are drained to almost empty. Sediment collects in the bottom of the tank and is drawn into the fuel filter when the gas tank is nearly empty. A fuel system cleaner can sometimes resolve this issue.
#8 Bad fuel pump
Bad fuel pumps are another step in delivering fuel to your car’s engine. At times they fail, become clogged, or wiring connections fail and starve your engine of fuel. Intermittent fuel supply to the engine causes engines to stall, surge and lose power. This can seem like the car is jerking as it receives fuel, and then it is cut off.
If the fuel pumps are clogged, make arrangements to have the fuel filter changed at the same time. It is quite probable that the fuel filter is also clogged as well and not delivering filter fuel to the pump.
The cost of replacing a fuel pump is relatively inexpensive, averaging around $450, but can range as high as $1000, depending on the make and model of the vehicle. Fuel filters are much less expensive and should be changed at the same time.
#9 Worn out accelerator cable on the gas pedal
A physical accelerator cable can gradually wear out on older vehicles. They may stretch and become slack, and occasionally they break, leaving your vehicle not driveable. The throttle cable connects the gas pedal in the driver’s compartment to the engine throttle plate.
As the gas pedal is pressed, the cable causes the throttle plate to open, and more fuel enters the engine. The cable could be sticking due to an obstruction or rust, leading to sudden changes in engine RPM and surging. Releasing the cable leads to sudden slowing of the engine RPM and subsequent vehicle speed.
If the cable is broken, the driver is unable to start the engine and use the vehicle. If you suspect a problem with a worn accelerator cable, have it repaired immediately before your car becomes disabled.
#10 Moisture on the distributor cap
Modern vehicles no longer have distributor caps, having moved to electronic ignition systems with coil packs. Older vehicles use a distributor cap to control the delivery of the spark to the spark plugs. A rotor rotates inside the cap, making a connection to posts that are connected to the spark plug and delivering high voltage electricity to the spark plugs.
Dirt and moisture sometimes find their way inside the car’s distributor cap, disrupting the flow of high voltage electricity to the spark plugs. The spark plugs may receive a weak voltage or none at all, leading to a lack of power to the transmission from the engine. A car parked outside in moist conditions can sometimes have this problem.
Once the moisture disappears, the cap should be fine. Drivers may remove the cap and dry it or wait until the moisture dissipates on its own. This problem can be reduced by parking the car inside in a dry area or using a thermal cover.
How do you fix a car jerking when accelerating?
There can be several mechanical and electrical problems that contribute to your car jerking while accelerating. The car may surge forward as it receives power from the engine and then suddenly loses power giving that the car jerks when accelerating.
At the top of the list is the check engine light illuminating, indicating that there may be an issue with one or more components affecting the air-fuel mixture delivered to the engine’s cylinders for combustion. Arrange to read the error code generated by the Engine Control Module and make the appropriate auto repairs at an auto repair shop.
Among the components that can cause jerking while accelerating and cause the check engine light to be illuminated are:
- Dirty fuel filters
- Bad fuel pumps
- Defective mass airflow sensor
- Dirty fuel injectors
- Dirty air filters
- A clogged catalytic converter
- The faulty transmission control module
- Bad spark plugs
- Warn out accelerator cables
- Moisture or dirt inside distributor caps on older cars
Make repairs to the component causing the check engine light to generate an error code, reset the error code and test drive your engine. There may be multiple problems causing your vehicle to be jerky while accelerating.
You may have to work through them one at a time until the problem is resolved. Don’t hesitate to make repairs or have your car checked and repaired to avoid being stranded on the road.
What causes a car to jerk when accelerating?
If your car jerks while accelerating, there can be several problems that contribute to this phenomenon. Our car engines have become very complex devices, controlled by Engine Control Modules and Transmission control modules.
These units are computers that control the flow of air and how much fuel is provided to the engine cylinders, the delivery of electrical sparks to ignite the fuel-air mixture, and environmental recirculation systems to manage the environmental discharge of gases from the engine.
The car’s computers rely on many sensors on the engine and transmission to monitor proper ignition, the flow of fuel, and the demands of the driver in terms of idle and acceleration requirements. Any of these sensors, as well as the components themselves, can contribute to the engine not performing in an optimum manner.
For example, a bad fuel pump that is operating intermittently can starve the engine of fuel at the time and suddenly deliver sufficient fuel to accelerate properly. A failing fuel pump may generate an error code to the ECM, and the check engine light is illuminated to indicate there is a problem that needs to be checked into.
For a full list of potential issues that can cause the car to jerk while accelerating, review early sections in this post. The solution can be as simple as replacing the cap in the ignition system, replacing the air filter, or cleaning a blocked air intake.
Can transmission cause a car to jerk?
Transmissions can cause the car to jerk. The TCM controls the shifting of gears to respond to the requirements of the driver to accelerate or to slow down, or to maintain road speed. The TCM relies on solenoids to control the transmission and to monitor conditions within the transmission.
Vehicles may have a combined Powertrain Control Module which incorporates the functions of both the ECM and the TCM. If any of these modules fail or are causing intermittent problems, drivers may experience jerking, failure to shift gears, or slow to shift gears. Faulty solenoids can also cause these types of problems.
Failing to shift gears can also be caused by insufficient transmission fluid in the transmission. You may hear a whining sound from the transmission, even at low speeds. Gear shifts will also be slower.
This condition should be remedied immediately, and drivers should check for leaking fluid under the vehicle. Check your car manual and only add the correct type of transmission fluid to the proper level to avoid damage to the transmission.
The check engine light may also illuminate, indicating that an error code has been generated. The code should be read using a code reading tool, and the appropriate repairs investigated and completed.
Car Jerks When Accelerating Replacement Cost
Replacement costs should range from $100 to as much as $2000, depending on the make and model of the vehicle. If the fuel tank in your automobile must be lowered to replace the fuel line, it may cost you over $500 because more effort is required.
One of the most expensive repairs you can encounter is a problem with the head gasket. The average cost of this repair is between $1,000 and $2,000, despite the fact that the materials aren’t pricey.
This sort of repair is essential to addressing as soon as feasible since it might lead to additional costly difficulties, including your car’s computer or even the ignition system. Another expensive solution to this situation in most cars is the need to purchase a new coil pack.
Sometimes a bad suspension system typically causes car jerks when accelerating at both low speeds and high speeds. Air mixes and other problems with the combustion process are simple to tackle when they are caught in the early stages.
A simple replacement of the air filter or the fuel injectors can resolve some of the issues making your car jerk when accelerating. So, if your car jerks when accelerating, be sure to have it fixed as soon as you can. Keep in mind that paying a little now can save money later on.
If your car is exhibiting jerking while accelerating at low speeds or highway speeds, there may be several issues that contribute to the condition. They should be investigated immediately to avoid damage to the engine or the transmission and also expose the occupants to dangerous road conditions.
The air-fuel mixture is compromised by the failure of a sensor or component, leading to poor power performance. In addition, a failing TCM or solenoid in the transmission can cause a car to jerk while accelerating.
The check engine light is often illuminated and should be checked. Use a code reader to read the error code your car produces and investigate the potential repairs that may be required. Various sensors and components may be faulty and need replacement. Faulty wiring harnesses can also cause this phenomenon.
Last Updated on: July 14, 2022