A running engine sends large amounts of electricity through the ignition system, which rotates the distributor. A distributor cap covers the distributor, and allows high voltage to pass through the ignition coil to the spark plugs. In order for your engine to run smoothly, it’s integral that the spark plugs fire in the correct order. If you’re looking for a high quality replacement product, look no further. We have an expansive range of ignition system parts for a large scope of vehicles. Shop low priced distributor caps by brand and registration at Parts for All Cars.