Attach the spark plug to a spark plug tester, then connect the tester to the ignition wire. Start the engine and observe the ...

To test the operation of both the ignition coil and the spark plug, connect the tester between the spark plug boot and the spark plug. Then start the engine and watch the tester window.

Check, replace and maintain the spark plugs in your car or motorcycle with this easy guide.

Keep your vehicle running in top shape by replacing the spark plug wires.

Car Care: Take cars that misfire to a repair shop, where their spark plugs and ignition boots should be checked.

A kit with some lower-profile 90-degree spark plug boots would be ideal, but for now a set of Accel's spark plug boot insulators (P/N 170086) should prevent damage.

You can use a multimeter to test the resistance to be sure. Q: How Can You Tell if a Spark Plug Is Firing? A: The grounding test is performed to determine if a plug is firing.