Why Does My Car Jerk When Slowing Down? Answer Here!

You should accelerate and decelerate smoothly while driving. But what makes your car jerk when slowing down? Is it a big problem?

Yes, of course. Several factors will cause your automobile to jerk, all of which are bad signs of damage. You need to find the root of the problem soon and eliminate it immediately. 

So what are the causes? We will discuss them today. Then, we also share how you can fix the issue. Follow us to discover!  

Why Does My Car Jerk When Slowing Down?

Your car jerks when downshifting because of the issue in the transmission, MAF sensor, clutch, throttle body, ignition coils, turbo, and engine mounts. What you need to do now is to identify which case you get stuck in before finding the solution. 

Faulty Transmission 

Whenever you decelerate, the transmission system will downshift to compensate. The shifts can’t work effectively if the transmission malfunctions, making your car jerk. 

It’s often the fault of the torque converter, a component that controls the rate at which the transmission and engine work together. 

Another issue in the transmission system is the lack of transmission fluids or transmission leaks. The leak comes from the damage to your car’s undercarriage. 

A problematic transmission can cause unpleasant vibrations, shaking, pounding, and other negative effects on your car that disrupt your driving. Even high-quality products like the Ford Windstar transmission  break down sometimes. 

When those transmission issues occur, your car jerks when braking at low speed or slowing down. So what should you do now? 

How to solve it?

Check the transmission jerk when decelerating first. The mechanic can help you replace this part to recover the performance of your car, giving you a smooth deceleration. 

Examine the underside of your car, too, to check for any signs of fluid pooling or dripping. If the fluid level is too low, add more. And if you see any cracks in the system, seal them. 

The cost for fixing the transmission depends on the problematic part. For example, you have to spend up to $3,000 to replace the whole transmission. Meanwhile, the cost to seal the transmission fluid leak can be as low as $100.  

Worn Clutch

The clutch in your car serves as the mechanical connection between the transmission and the engine. It also helps separate the motor from the transmission system.

When you step on the pedal, the clutch will cut off power to the driving wheels, allowing you to easily change gears.

When a clutch becomes worn out or broken, it can’t handle the connection between the engine and transmission and will start to rev up at leaden speeds. This situation makes your car jerk when decelerating.

How to solve it?

You can confirm if the clutch is the root of the problem by checking for weird sounds and vibrations while slowing down. Then, replace some clutch components to fix the problems. 

A clutch comprises five components: cover plate, driven plate, pressure plate, release bearings, and diaphragm springs. It would be best to check all of them to diagnose the issue. 

Faulty Throttle Body

The throttle body can regulate the amount of air entering the engine. Hence, it affects the power output and speed of your engine. 

When the throttle body is faulty, your car will jerk when slowing down because it can’t handle the supply of air and fuel correctly. Stalling and rough idling are other consequences of the bad throttle body. 

Sometimes, the clogged throttle body prevents your car from starting. You can only run after giving it gas.

How to solve it?

If the throttle body fails due to dirt and debris accumulation, you can clean it using specialized cleaners. But it’s the least severe case. 

If the throttle body has gotten damaged, you have to replace it. A qualified mechanic can perform this task properly. 

Faulty MAF Sensor

The MAF (Mass Air Flow) sensor is part of your automobile’s electronic fuel injection system. It has an internal heating element that helps compute the air to the engine. 

If the MAF sensor fails, it can’t estimate the airflow rate correctly. As a result, your car runs improperly at low speeds. You also have difficulty speeding up. 

How to solve it?

You can try resetting the MAF sensor to delete the old data so it can work with the new one effectively. 

However, if the reset doesn’t work, call a certified mechanic to check the condition of your MAF sensor carefully. He will perform some tests to identify the risks and eliminate them.

Damaged Ignition Coils

Ignition coils give sparks to ignite the air/fuel mixture in the engine and make it run. If these coils are faulty, there can be a misfire. 

The engine misfire will lead to poor air/fuel burning. Your car can’t go smoothly when slowing down because of the weak ignition. 

How to solve it?

If you suspect that the faulty ignition coils are causing your car to jerk at slow speeds, replace them as soon as possible. 

Damaged Turbo

The turbochargers provide the engine with extra power while maintaining fuel efficiency. They are popular in small engines that want to improve their performance. 

Sometimes, the damaged turbo causes your vehicle to jerk when decelerating. It makes the engine run at different speeds and finally jerk. 

How to solve it? 

In situations like these, you need a professional checkup to determine the severity of the damage. If necessary, the mechanic will fix or replace the turbo. 

Unfortunately, this repair is costly. However, you have to do it to help your automobile recover to its normal condition. 

Worn Engine Mounts

The engine mount, as its name implies, is a component that keeps the engine in place. Since the engine and transmission are bolted together, the mounts hold them securely to prevent them from moving around. 

If the engine mounts erode, they can’t move up and down normally. Your car may get shocked because it slacks off speed. 

How to solve it?

You need to perform a vibration test to check for any problems with the engine mounts. Then, replace them if they make your car jerk when slowing down. 

How Much Is It To Fix A Car That Jerks When Slowing Down?

Most of the time, you must take your car to the garage and fix it. The cost for this service varies depending on the cause. For example:

• Transmission repair: An average repair cost ranges from $300 to $1,500. If you just need to replace the clutch, the cost will be around $800. However, the entire transmission replacement costs from $1,800 to $3,400. 
• Transmission leak: If you want to fix the transmission fluid leak, you will pay around $150 to replace the seal. Otherwise, a new torque converter costs about $1,000. 
• MAF sensor: The cost to replace a MAF sensor is around $200, with a labor fee of $20 to $100. 
• Ignition coils: An ignition coil costs $30 to $300, depending on your car model. Besides, you have to pay for the labor cost of less than $100. 

Conclusion

What makes your car jerk when slowing down? You can blame the faulty transmission, clutch, throttle body, MAF sensor, ignition coils, turbo, and engine mounts for this issue. 

Over time, those components will erode or get damaged. You should fix them soon or replace them if needed. The mechanic will help you decide what your car needs to recover. 

Hopefully, your car can slow down and speed up smoothly after the treatment. If you experience a different case, please share your story with us. We are always ready to help. 

Thank you for reading!