Check spark plug wires to ensure smooth operation

Spark plug wires are fairly durable. But if one does get damaged, it can make your car run rough and severely effect gas mileage.

Each spark plug wire is connected to a spark plug, and brings the electrical spark to the spark plug in order to ignite the fuel inside the engine's cylinders. The only thing that can really go wrong with a plug wire is a break in the insulation. The insulation -- the rubber on the outside of the wire -- keeps the electricity where it needs to be so it sparks on the inside of your engine, not someplace else before it gets there. If the insulation is cracked, the spark will jump off the wire, or arc, onto something metal under the hood.

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A careful inspection of your plug wires can avoid any problems. So pop the hood and do a quick inspection of your spark plug wires to see if they need replacing ... and do it often.

Here's how:

• Open the hood and locate the spark plug wires. They can be black, blue, red or orange.
• Remove the spark plug wires one at a time. They must go back on the distributor cap in exactly the same order they came off, or you'll have changed the "firing order" and your car may not run at all.
• With your engine off, start at the distributor end of the plug wire and work your way toward the plug end. You're looking for anything that is not smooth, pliable rubber.
• Carefully bend the wires slightly to be sure no cracks appear.
• Check the boots at the distributor end of the wires to be sure they are not torn or cracked.
• Check the wires at the spark plug end one at a time by pulling it off the plug and inspecting the end for any tears or cracks. Also check to be sure there is no burning or darkening of the end.

Spark plug wires should be changed when they start to become hard or inflexible, or look dry and cracked. If one wire fails or you find a damaged wire during inspection, it's probably time to change them all.

Changing spark plug wires is fairly easy and usually requires no tools. For helpful, how to videos to guide you through spark plug wire installation, click here.