A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. Spark plugs have an ...

Read a good spark plug lately? We hope so, for your engine's sake. But spark plug reading—the traditional way to check your fuel mixture and monitor other vital conditions in the combustion chamber ...

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 ...

For the average stocker in good running condition, spark plug selection is a cinchchoose whatever brands on sale, look up the plug part number in the catalog, and go down the road. At the opposite ...