Spark plugs that haven't been changed for a long time can become one with the cylinder head. Fortunately, it's possible to repair damaged threads instead of scrapping the head. (Photograph by Chris ...

The gap between the center and side electrodes needs to be an exact distance across; otherwise, your plugs won't fire efficiently. Remember: Gap new as well as old spark plugs, even if the package ...

A healthy ignition system is key to a car's overall efficiency and power output. If any of the components that have a hand in lighting off the air/fuel ratio are damaged or worn out, it could mean a ...