Can Bad Spark Plugs Cause a Car To Shake?

Bad Spark Plugs Cause Car to Shake

Bad spark plugs can trigger a lot of issues in your car. From causing your vehicle to run rough, affecting your drive performance, and in rare cases, starting a “check engine light,” bad spark plugs can be a thorn in the flesh. Amidst the numerous problems that a bad spark plug brings, can bad spark plugs cause a car to shake?

Yes, bad spark plugs can cause a car to shake, but it depends on certain factors. This includes the number of cylinders your car engine has and the number of faulty plugs in your vehicle. Spark plugs are major components of the ignition system.

When there is a poorly functioning spark plug, there is an imbalance in the firing order from the cylinder to the combustion chamber. Your engine’s number of cylinders will determine how rough the vibrations will go. You should expect a noticeable vibration from an engine with a four-cylinder engine.

Let’s learn how bad spark plugs can cause a car to shake and why they do so!

Can bad spark plugs cause a car to shake?

Yes. Bad spark plugs can cause a car to shake. Bad spark plugs usually cause engines to misfire, but we’ve noticed that they can also be responsible for the vibrations in your vehicle. These vibrations/shakings are typically noticeable when your car is idle or running at low speed.

Bad or worn-out plugs find it challenging to produce the required sparks and electrical energy to ignite the air/fuel mixture to supply your engine with power.

The spark plugs, though tiny, generate an amount of electricity that creates an explosion that ignites your car’s combustion, making it easy to start. When this operation is tampered with, either by a rich air-fuel mixture or oil or carbon coating on the spark plug, the engine will misfire.

This can go as far as triggering vibrations from your car’s engine until the whole car starts shaking. However, the degree of vibrations and shakes caused by the spark plug is determined by the number of cylinders in the engine against the number of faulty plugs.

A V8 or V12 engine will shake less if one spark plug misfires, compared to the vibrations that will erupt from a 2-, 3-cylinder or I4 engine if one plug is not firing.

Can bad spark plugs cause shaking at idle?

Yes. Bad spark plugs can cause shaking when your car is idle. If a plug goes bad that it loses its sparking ability, making it malfunction when the engine is running, it will result in a nonfiring cylinder which will trigger shaking at idle.

This will make your engine perform abnormally during combustion, resulting in misfiring and random shaking.

The “shaking effect” at idle is usually not limited to the spark plugs. It would be best if you considered changing the coil that supplies spark voltage through the plug. Other factors can cause your car to shake at idle.

Here are certain things that can cause your car to shake when idle:

What does it mean your car is shaking while driving?

Your car shaking while driving can mean a lot of things. It can indicate that you have unevenly worn tires; bad, damaged or bent wheels; issues in your steering and suspension system; or bad brakes. Your car is shaking while driving means that your vehicle is not properly balanced.

The degree of the shaking/vibration can help you detect how severe the damages are and how close you are to a fatal accident. Sometimes, you might not notice your car shaking until you reach 60 mph.

Other minor reasons that can cause your car to shake while driving includes bad bearings and damaged axle components.

Can old spark plugs cause a car to shake?

Yes. Old spark plugs can cause cars to shake. This happens when there is a high possibility that an old spark plug is dirty, worn out, or even broken. This will make the spark plugs malfunction, making them ineffective in igniting the combustion chambers.

When the spark plugs fail to fire properly, they can cause the engine to misfire or, in extreme cases, cause the car to shake from the engine.

Why is my car shaking at idle?

There are a lot of reasons why your car is shaking at idle. Your car can shake at idle if the engines are not firmly supported. This happens if the motor mounts are broken, causing the engines to shake and move vigorously.

The shaking can extend to the entirety of the car. Your car will also shake at idle if your fuel injectors are clogged and cannot deliver a sufficient amount of fuel to your car. A rich fuel-air mixture, poorly fitted vacuum hose, and worn-out belts are some of the reasons why your car is shaking at idle.

You need to figure out the right problem.

Why is my car still shaking after replacing spark plugs?

There are a few reasons your car is still shaking after replacing spark plugs. Your car would continue shaking after replacing the spark plugs if a bad spark plug wasn’t the initial reason for the shaking. There are also chances that you didn’t properly install the new spark plug.

You should check if you connected the wires to the plug, look for the coils, and check if the ignition leads are correctly fitted. You should also confirm that there aren’t other damaged spark plugs you didn’t notice.

We advise you to visit a mechanic if you are out of options for what is causing your car to shake after replacing the spark plugs.

Why does my car shake when I drive but stopped?

You should not believe your car is now fine if it shakes while driving but automatically stops. It might indicate that some of your car’s components are gradually damaging and might only cause your car to start shaking when accelerating to a certain level or turning in a certain direction.

It would help if you inspected your wheels, bearings, and mounts.

Also, look out for vacuum leaks and spark plugs.

When I press the gas, my car shakes

One of the major reasons why your car shakes when you press the gas is that your engine is misfiring or you have a broken motor mount.

A broken motor mount will move your engine about vigorously when you hit the gas pedals. Other factors that can cause your car to shake when you press the gas includes:


You must understand that even though bad spark plugs can cause your car to shake, they are not the only factors that could be responsible.

While we believe this article will guide you in making informed decisions, we will advise that you employ the services of a professional mechanic. Proper diagnosis will serve better than random guesses.