The ignition system in your engine bay handles electrical loads of thousands of volts to get a clean spark to your spark plugs. The distributor receives the electrical current from the ignition coil and distributes it to the spark plug wires, which carry the current to the plugs. A spark plug wire set is an important component to the running condition of your car. As it ages, the ability to transfer electricity goes down, causing poor performance. This manifests itself as hesitation, rich fuel mixture, poor fuel economy, and occasionally misfires. It’s smart to replace the distributor cap, rotor, spark plugs, and spark plug wire set all at the same time for the most effective ignition system service.