Is Your Car Jerking? Here Are the Possible Causes

Being in a lurching, juddering, or jerking car while on the road can be scary. It’s one thing if your car shudders when it’s parked and idling but when the jerking happens while you’re driving at speed, it could take you by surprise and even cause you to lose control of your car. A jerking car could signify a number of issues from a dirty air filter to a clogged catalytic converter. And if left unchecked for too long, the issue could cause major, more costly problems.

Car jerking stressed woman driver

What It’s Like When Your Car Is Jerking

When your car jerks, it often feels like it’s struggling to move forward even when you press down on the accelerator pedal. Depending on the severity of the problem, your car could have just minor shaking, or, in some cases even hesitate for a second and then lunge forward when you put your foot on the pedal. 

If your car is jerking while accelerating from a stop, it makes it hard to pick up speed and can be annoying especially in stop-and-go traffic. However, things can get dangerous if your car jerks when you’re already driving at speed as you could suddenly slow down and cause a collision. 

Read: What do Your Car Warning Lights and Indicators Mean

What Can Cause a Jerking Car?

A jerking car can be caused by a number of issues. While some are easily fixed like replacing a dirty air filter, some signs require more attention. Many issues that cause your car to jerk can trigger the Check Engine Warning Light, so if you notice any of these, be sure to get your car checked.

Worn Out or Damaged Spark Plugs

Spark plugs are responsible for delivering the electric current from the ignition system to the combustion chamber. This “spark” ignites the mixture of fuel and compressed air which then moves the pistons in your engine cylinders. If you have faulty spark plugs, the fuel can’t ignite properly and the cylinders will misfire. This misfiring can cause your car to jerk when accelerating, while maintaining speed as well as vibrate excessively when idling. Fortunately, you can fix this issue by replacing the spark plugs, which are generally affordable and should be part of your regular servicing schedule.

Dirty Air Filters

The air filter functions to prevent dirt and debris in the air from entering the engine. If it’s dirty, it could restrict airflow to the engine, thus reducing the amount of oxygen that the engine gets. This causes an uneven oxygen-to-fuel ratio in the engine which leads to misfiring and car jerking. Oftentimes, the engine compensates for this by consuming more fuel to produce the same amount of power which then affects fuel economy. To prevent this, it’s important to regularly replace your air filter during each scheduled service.

Dirty Fuel Filters

Like an air filter, the fuel filter screens dirt and debris in the fuel. If it gets dirty, it could prevent enough fuel from getting to your engine causing jerking in your car. However, a dirty fuel filter could cause other issues including reduced engine performance especially under heavy acceleration, stalling while driving, and hard starting. If left unchecked, a dirty fuel filter could cause other parts of your fuel system to fail. For instance, your fuel pump could work harder to supply more fuel to the engine which may cause the pump to overheat and break down.

Clogged Fuel Injectors

The fuel injectors send a steady stream of fuel into your car’s engine cylinders. When a fuel injector gets dirty, it won’t be able to deliver the right amount of fuel to your engine quickly enough. In the end, the fuel won’t get properly ignited which causes misfiring. Car jerking due to dirty fuel injectors is fairly rare, but fuel injector issues can lead to engine failure so it’s important to check it out. 

To prevent clogged fuel injectors, you can regularly clean them with fuel injector cleaners – just pour the cleaner into your fuel tank according to the product instructions and you’re done. You can also consult your mechanic to find out more about fuel injector cleaners that they recommend.

Read: Why Your Car Breaks Down & How to Get Help

Malfunctioning Mass Airflow Sensor

The mass airflow (MAF) sensor measures the amount of air that your engine gets. This data is then used to adjust the amount of fuel that the fuel injector should supply to ensure the right oxygen-to-fuel ratio is maintained. With a defective MAF sensor, the fuel injector might end up sending the wrong amount of fuel to the engine, causing a host of problems. 

Your car could end up jerking when accelerating or while maintaining high speeds. Your car could even have difficulty starting and could shake or stall while idling. If ignored for too long, a defective MAF sensor could cause your car to have reduced fuel efficiency and poor emissions. In extreme cases, it could cause the engine to seize, meaning it gets locked up and is unable to start. Depending on the extent of the damage, fixing a seized engine can be extremely difficult and expensive, so make sure you get your car checked if you encounter these problems.

Check car engine

Blocked or Damaged Fuel Line

A blocked or damaged fuel line could be another reason why your car is jerking. The fuel line transports fuel throughout your engine and when there’s a cut or clog in the fuel line, there could be uneven fuel pressure to the engine. The low fuel pressure will cause your engine to misfire, which leads to jerking. If left unchecked, the leak from the damaged fuel line could even cause your engine to catch fire.

Transmission Issues

There are a number of transmission issues that can cause your car to jerk. If you have low transmission fluid, your car could shake or shudder when idling. You could also find your car jerking or lurching violently when accelerating from a standstill. Another issue that could cause your car to jerk is a malfunctioning transmission control unit (TCU). The TCU controls the shifting of your car as you accelerate so a malfunctioning one could cause your car to shift gears inconsistently or slowly which leads to your car jerking.

Clogged Catalytic Converters

The catalytic converter reduces the exhaust particles that your car emits. However, if it becomes clogged, it could cause an exhaust buildup which reduces airflow in your exhaust system. The obstructed airflow can cause jerking in your car and a number of other issues. Besides causing your car to jerk when accelerating, at speed, or while idling, a clogged catalytic converter could affect the fuel economy of your car and even increase your car’s exhaust emissions. If you notice that your car is jerking, consuming more fuel, and spewing out more smoke, then you could have a clogged catalytic converter.

While you can still drive a jerking car if the occurrences are minor or few and far between, more frequent and stronger jerking when maintaining speed could mean there are serious issues with your car. If you notice something off about your car, get it checked by a mechanic as soon as possible. Jerking may develop from a minor issue into a more major, costly issue.

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