Spark plug

A spark plug is an electrical component used in internal combustion engines, such as those found in cars, boats, and lawnmowers. It introduces a spark which ignites gasoline vapor to cause an explosion. In modern cars, they are commonly changed around 100,000 miles, along with their associated wiring.

Diesel engines do not require spark plugs. They operate under higher pressures and ignite their fuel using glow plugs instead.