Add Yahoo as a preferred source to see more of our stories on Google. But spark plugs live in harsh environments. Not only do they see massive changes in temperature, but schmutz tends to accumulate ...

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 ...

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 ...