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 ...

How often you replace spark plugs depends on the type of plugs you have. You may have 30,000-mile plugs, or if the plugs have platinum tips, they may be good for up to 100,000 miles, although some ...

It doesn't matter what type of vehicle you drive or which type of spark plug you're using. If your car has an internal combustion gasoline engine, it has the potential to eject a spark plug — although ...

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 ...

For hot rodders, spark plugs are often nothing more than inspection tools that reveal whether an engine is running too rich, too lean, or just right. Street guys look for a nice tannish-brown tint on ...