Caution: Use electrically insulated pliers when handling spark plug wires, with the engine running. Use care to prevent an electrical shock.
Notice: Twist the spark plug boot one-half turn in order to release the boot. Pull on the spark plug boot only. Do not pull on the spark plug wire or the wire could be damaged.
The spark plug wiring has an outside insulation layer of silicone. The silicone spark plug boots form a tight seal on the spark plugs. The wire boots also seal around the distributor cap and ignition coil terminals. This tight seal prevents voltage arching.