Spark plugs are a small yet significant part of a vehicle’s engine, that play a significant role. If your vehicle has bad spark plugs, it may fail to even start or run. Read on to find out more about spark plugs, their importance, types of spark plugs, their life span and how to know when and if you need a spark plug replacement.

What are Spark Plugs, and What do they Do?

As mentioned before, spark plugs are a small yet significant part of a vehicle’s engine. Without these, a vehicle is practically useless. Spark plugs serve the important purpose of supplying the spark that ignites the air-fuel mixture. This then gives rise to the explosion which then makes your vehicle’s engine produce power. Spark plugs serve as electrodes or conductors of electricity. They have two leads which do not touch but are close enough in distance that this spark plug gap does not disturb the flow of electricity. A vehicle’s spark plugs, electrical equipment and timing equipment all form part of what is known as a vehicle’s ignition system.

Spark plug wires are generally highly durable enough to withstand many explosions. This means that it is generally a long while before you need to replace spark plugs. However, over time the spark plugs will wear down and become weaker meaning that you will need new spark plugs. This is because weakened spark plugs lead to the idling of your vehicle’s engine.

Does My Car Need New Plugs?

There are a few signs that tell you if your vehicle is suffering from worn-out spark plugs. Some of these include

  • Misfires -this is usually caused by malfunctioning ignition coils and faulty spark plugs. This is also referred to as an engine misfire and occurs when one or more engine cylinders of the engine failed to produce power or as we’ve mentioned worn-out spark plugs.
  • Rattling noises – engine misfire often causes some unusual noises. Spark plugs misfiring at the wrong time cause rattling sounds.
  • Reduced performance – when a vehicle’s spark plugs are not performing at their best, it impacts the vehicle’s performance 
  •  Your vehicle giving you trouble starting – this is an obvious sign that something significant is wrong. Faulty spark plugs will lead to engine misfires as well as emissions which in turn affect the vehicle’s overall performance and how it starts. 
  •  Poor gas mileage – one of the things that can lead to poor fuel economy is faulty spark plugs. This is because your vehicle will tend to waste a lot of fuel if it fails to receive the correct amount of spark at the correct time 
  • Rough idling – this is another term for trouble starting.

If you are someone who follows a maintenance schedule then it would be very helpful to take a look at your car’s owner’s manual to know the life span of your car’s spark plugs as well as the general car care it needs, such as when to have oil changes and more.


Changing old spark plugs is a very important part of any car maintenance. So the next time you visit an auto repair shop make sure to have them check if your vehicle needs new plugs.