Signs You Need To Replace Your Spark Plugs

Spark plugs are a key component of your vehicle's ignitions system. Improperly functioning spark plugs can pose a variety of issues, the most notable of which being the inability to start your car, which can leave you stranded at short notice. Thankfully, there are a number of warning signs that you can look out for to tell when your spark plugs are nearing the end of their lifespan and need to be replaced. 

Problems Starting

Perhaps the most severe, yet most noticeable warning sign of failing spark plugs is difficulty starting your vehicle. This can manifest itself in your engine turning over several times before catching, or taking several turns of the actual ignition before it starts running. When coupled with low temperatures, it may take several minutes for your car to start. However, even you find it difficult to start your car, you should verify with a mechanic to ensure that spark plugs are the issue: sometimes a dead battery can also be at fault.


Engine misfires are when the engine fires at the wrong time, usually resulting in a loud noise and a rougher engine running sound for a few seconds before it manages to even out again. The more often your engine misfires, the more severe your spark plug wear is. Engine misfires can cause increased engine wear, which can lead to additional problems with your vehicle, and thus should be examined at once.

Reduced Fuel Efficiency

Spark plugs that aren't functioning properly anymore can lead to a rougher running engine that uses more fuel to power the vehicle. This will manifest itself in a number of ways, including reduced fuel efficiency. If you notice that you are filling up your gas tank at an increased rate despite no changes to your driving habits, you may want to get your spark plugs looked at. However, it should be kept in mind that reduced fuel efficiency can also be attributed to a wide range of other issues, including poor tire inflation.

Rough Idling

An engine that is idling should sound smooth and be fairly quiet. However, a damaged or worn down spark plug will result in a rougher, louder idling sound, which can also manifest itself as a vibration of the entire vehicle, and is usually accompanied with engine misfires as well. Rough idling should be investigated immediately by a mechanic (such as one from Southside Auto Repair), as it can lead to increased engine wear and other more expensive problems.