Nissan 22401-30R15 Spark Plug

A spark plug, made of a metal shell and ceramic insulator, houses two electrodes with a gap for current to arc, igniting the air/fuel mix in the engine. The plug doesn't create the spark, but facilitates it. Datsun/Nissan plugs have a built-in resistor to reduce interference. Spark plug efficiency depends on engine condition and temperature, and they should be replaced every 30,000 miles. Worn plugs can cause misfiring and reduced performance. When replacing, remove one at a time, clean around the plug, check for wear and correct gap, lubricate threads, hand tighten, then use a socket. Reattach wires to correct plugs.