Many drivers think that when their car isn't starting that there is a problem with the battery. Sometimes this is the case but not the only possibility. Your cars spark plugs could be the culprit! After all, these small components have a big job to do! There are several factors that contribute to spark plugs going bad. Overtime, the constant exposure to high temperatures and the sparking process will wear down the electrodes. If the air-fuel ratio isn't correct, carbon deposits will accumulate on the plugs and prevent them from firing correctly. How do you know if your spark plugs are bad? Worn or failed plugs can trigger your check engine light to come on. One of the most common symptoms of a bad spark plug is your engine stuttering or jerking or if the vehicle is idling rough. If your car doesn't accelerate as quickly as it used to or if it feels sluggish, this could be due to a worn spark plug. Spark plugs don't wear out very quickly but their lifespan can vary on the type of plug and your driving habits. Typically, you can get around 50,000 miles on spark plugs before replacing them.