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 space, or gap, between the center and side electrodes needs to be an exact distance across; otherwise, your plugs don't fire efficiently. Adjusting the distance between the two electrodesis called ...

You can (and should) actually read your spark plugs for valuable "clues" about how your engine is operating. To read your spark plugs, follow these steps: 1. When you get the first spark plug out of ...