Spark plugs are small car components, but they play an oversized role in keeping your engine running. It's critical to know when they need replacing.

We may receive a commission on purchases made from links. When it comes to engine care 101, a spark plug replacement — also referred to as a tune-up — is an essential task. Spark plugs, as the name ...

You're hunched over the engine with your wrist painfully contorted, wishing you were Mr. Fantastic. You've finally removed broken spark plug number four and then the intrusive thought hits. "Should I ...