Plug wires wear out with time. How often you change plug wires is a personal choice. I do it every year or two. When your engine doesn't seem to be running well, or a miss develops, it could be the wires. Plug wires crack and break. Or you may have broken one when you changed your plugs last.

If you are looking for top performance, good plug wires are real important. There are different kinds of plug wires for different applications. The plug wires carry the electric spark from the coil through the distributor to the plugs. The plugs use that electricity to ignite the fuel in the cylinders. If that process is not efficient, your car will not run properly and you won't be getting maximum horse power. The kind of wires used on race cars are not the best to use in a street car. If for no other reason, they aren't shielded and will interfere with your radio. Street plug wires have a graphite core. Graphite is a good conductor of electricity. However, graphite will also break if the wire is abused, like pulling on the wire to get it off the plug.

If your car is running real poorly here is a old mechanics tale that actually is true. At night time, start your car up, open the hood and look for arcs or sparks of electricity in the dark. If you see that you are way beyond time to replace the wires. I've never seen it, but then I replace the wires pretty often.

A word of Caution: If the car is running do not grab the plug wires. Your coil sends out a pretty high voltage of electricity down these wires. Newer cars and racing type coils put out a lot more. It can knock you on your butt or worse. Take my word for this.

Step one: change ONLY ONE PLUG WIRE AT A TIME. Your car has a firing order. You don't want to have the cylinders fire out of order. Replace each wire, individually at the distributor and at the plug. Make sure that the wires snap onto each plug and into the distributor cap. I pull the boot back from the ends. Slide the distributor end into the cap then slide the boot onto the cap.

Its about that easy. The only places you can screw up is: 1) not getting the plug wires IN TO the distributor cap or not snapped on to the plug or 2) removing more than one wire at a time and getting the firing order messed up or 3) pulling on a wire and breaking the core.