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Why Are You Hearing A Bad Spark Plug Sound?

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The spark plug of your car is responsible for igniting fuel in the combustion chamber. The spark plug is thus a very important component of the internal combustion engine. A faulty spark plug is thus not at all a desirable condition as it even leads to the complete breakdown of the car and the production of a bad spark plug sound. 

In this article, all common bad spark plug symptoms that lead to the production of annoying sounds from your car are discussed. So read on to find out!

Spark Plug: A Critical Component Of Your Car

As mentioned above, spark plug is one of the most critical components with the duty to ignite the fuel in the combustion chamber. Spark Plug is designed in such a way that it can transmit an electrical signal from the ignition coil to produce a spark that ignites the air-fuel mixture in the combustion chamber at a predetermined time. Each vehicle has specially designed spark plugs made from specific materials to meet the needs. When good spark plugs burn efficiently producing enough sparks, bad spark plugs can cause the car to not start at all along with the production of bad spark plug sound.

Spark plugs, like motor oil, fuel filters, and air filters should be given regular maintenance service to let your car’s engine work smoothly. The spark plugs of a lot of vehicles that are available in the market need replacement after 30,000 to 50,000 miles. Identifying the several bad spark plug symptoms are thus very important to maintain your vehicle in good shape. 

Why Am I Hearing A Bad Spark Plug Sound?

You will notice several unpleasant sounds from your car when it has a bad or failing spark plug. There are some other symptoms too that communicate with you about failing spark plug including slow acceleration, loss of power, poor fuel economy, engine misfires, and difficulty starting the car. These symptoms are serious and even though there may be other reasons why these are seen, the most important reason is mostly a bad spark plug. 

1. Slow Acceleration

A failing or bad spark plug is one of the most common reasons why you may find it difficult to accelerate your car. A faulty ignition system or a bad sensor is usually the ones who are blamed when your car has slow acceleration. But along with slow acceleration, if you are hearing a bad spark plug sound, you can conclude that your car is having a worn-out spark plug. 

Spark plugs are mostly made of components that can produce spark to ignite your car’s engine when needed. When these materials or components wear out, sparks can’t be produced properly or at all which can reduce the acceleration of your vehicle. 

It is advised to contact your trusted mechanic if you start noticing such a symptom in your car as soon as possible. A timely repair can save you a lot of money or otherwise such a situation will lead to complete damage to your spark plug. 

2. Poor Fuel Economy

A fully functional spark plug burns fuel very efficiently that leads to a very good fuel economy. However, if your spark plug is faulty, the fuel won’t be burnt well leading to poor fuel economy in your vehicle. So if you feel that your car’s fuel economy decreased all of a sudden, the problem is most probably with the spark plug. 

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This condition mostly happens when the spark plug electrode of your car is either too close to each other or far from each other. Re-adjusting the positions of the electrodes mostly cures the issue of poor fuel economy. 

3. Engine Misfiring

The most common symptom that can be associated with bad spark plug sound is engine misfiring. You can identify engine misfiring by noticing unusual stumbling or sputtering noises coming from the engine of your car. This symptom occurs mostly because of a bad or failing spark plug which needs to be replaced immediately. 

4. Engine Surging Or Hesitating

If you notice that your engine is hesitating to start or accelerate along with making unusual sounds, you can conclude that your car has a failing or bad spark plug. Your engine may also suddenly surge to power and then slow down. This happens because your engine is trying to suck in more air than usual for combustion causing a delay in power delivery. 

5. Rough Idle

This is another case associated with sound created due to a bad spark plug. You will notice a bad spark plug sound almost like jittering while idling. This is a symptom caused only due to a bad or faulty spark plug in which a cylinder misfires while idling. 

6. Hard To Start

If you are finding it hard to start your vehicle, there could be an issue with the spark plug. The ignition system of your car comprises several components that must work properly to start your car without any issues. It is best to get your car checked by a mechanic as soon as you find it difficult to start your vehicle. This will help you solve the problem without having to spend a lot of money and also save your car from further damage. 

Even if your spark plug is fine and the reason for the difficulty in starting your car is different, if you ignore the situation, your spark plug will eventually wear out. 

What Should Be My Next Step?

If you want to stop hearing annoying sounds that are caused because of a bad or failing spark plug, the next step you should adopt is to find a good mechanic to fix the situation. Take your car to a mechanic or get your car checked by one and do the necessary according to what their instructions are. Get your spark plug repaired or even replaced to stop the annoying sounds and other symptoms that are caused by a spark plug as soon as possible. If you are fast in getting the situation fixed, you will be able to save a lot of money. Otherwise, a bad spark plug can cause further damage to your ignition system and engine which may require you to even replace them too. 


Having to hear unusual sounds that are caused by a bad spark plug while driving can be a cause of annoyance. Never ignore them and other symptoms that are discussed in this article caused by a bad spark plug. Do the necessary immediately and save yourself and your car from any further damage.