An internal combustion engine needs three things to get going: Air, fuel, and spark. The throttle body and intake plenum feed air, while injectors spray the right fuel mix into the combustion chamber.

Dear Tom and Ray: Yesterday, my son broke off a spark plug in his 1989 Ford F-150 with a six-cylinder engine. It broke off flush with the hole. Egad! How do we get the rest of the spark plug out, and ...