Top Reasons Bad Spark Plugs Cause Rattling

Bad Spark Plugs Cause Rattle

Bad spark plugs can cause rattling. This is usually evident in older cars that have high mileage. Bad spark plugs usually cause car engines to misfire, but in most cases, the faults can extend to jerking, vibrations, and severe rattling. This frequently happens when the car is on load or accelerating.

When bad spark plugs cause your engine to misfire because there isn’t a proper fuel-air mix ignition, your car will run rough at idle and start shaking vigorously. This means that a bad spark plug will not cause your car to rattle but will trigger systems that will do so.

Let’s quickly learn more about how bad spark plugs cause rattle in cars!

Can bad spark plugs cause rattle?

Yes, as I stated earlier, bad spark plugs can cause your car to rattle! The degree of rattling experienced in your car is dependent on how bad the spark plugs are and their reactions to your engine. This also depends on the number of bad spark plugs your car is running on against the number of available cylinders.

The rattling caused by a bad spark plug is from its inability to ignite the cylinder. The imbalance in your engine’s firing order because of a bad spark plug will trigger a misfiring, which will cause the car to rattle. In most cases, the rattle is not noticeable.

The amount of “rattle disturbance” depends on the number of cylinders your engine has. For instance, an Inline four engine with four cylinders will rattle much if its spark plugs go bad. The lesser the engine cylinder has, the more rattling you will experience.

What does an engine sound like with bad spark plugs?

Your engine should produce strange sounds if you have bad spark plugs. These sounds might largely differ depending on the faults or how bad the plugs are. A bad spark plug will cause your engine to produce knocking, racking, or rattling sounds.

Bad spark plugs usually cause these sounds because your engine is running rough. In most cases, the engine knocking sounds are not just because you have blown spark plugs.

The noise will increase in your engine when your car is under heavy load or accelerating. The noise will sound like metallic components rubbing together.

Why does my car sound like it’s rattling?

There are a lot of factors that can make your car sound like it’s rattling. Bad spark plugs are not the only things that can make your car rattle. Some of the common reasons why your car sounds like it’s rattling include:

To ascertain why your car is sounding like it is rattling, you need to diagnose if it rattles when your car is idle when you are at high speeds or under great loads. The position where the rattle sounds are coming will also give you a head start.

The cause of the rattling sounds from your car might be a minor issue, as little as a loose trim, loose car compartments, or failing interior parts. It can also be an engine-related problem like a piston slap or rod knocks.

You will need the services of a professional mechanic to help diagnose and repair the reason why your car is sounding like it’s rattling.

Can bad spark plugs cause loud engine noise?

Yes. Bad spark plugs will cause loud engine noise. However, this noise usually depends on the engine your car is running on and the proportion of the number of cylinders against the bad spark plugs.

If your car runs on a four-cylinder engine, you should expect a loud noise from a bad spark plug. This is because your car’s misfiring and rough running will be noticeable. This is compared to a V8 engine that runs on eight cylinders.

What happens if you keep driving with bad spark plugs?

A few things will happen if you insist on driving with bad spark plugs. If you keep driving on bad spark plugs, your car will experience misfires, poor fuel economy, rough idling, and sometimes a lack of acceleration. The issuse can extend to engine malfunction.


You must understand that bad spark plugs will cause your car to rattle. Rattling sounds are great indicators that you have a bad spark plug. However, other factors can cause the spark plugs to go bad.

A professional mechanic will help inspect, suggest the best solution for the rattling, and fix them.

Frequently Asked Questions

Will bad spark plugs throw a code?

Yes. Bad spark plugs will throw a code. The code from a bad spark plug might not specifically tell you that you have bad spark plugs. It will occur because of the resulting causes of the bad spark plug.

Should I replace all spark plugs at once?

Yes. You should replace all spark plugs at once if you notice a bad spark plug in any of them. It might sound cost-effective to change only the damaged spark plug, but you need to replace all the spark plugs simultaneously to achieve consistent driving performance.

How often do spark plugs need to be replaced?

There is no general rule on when your spark plugs must be replaced. It would be best if you changed the spark plugs as soon as they go bad. On average, spark plugs should last between 10,000 and 30,000 miles. It greatly depends on how frequently you use the car and the heat levels they are exposed to.