When to Replace Spark Plug Wires

I was asked the other day to look at a set of spark plug wires to see if there was a problem with them. Well, it’s not very easy to just visually inspect spark plug wires for problems.

I Mean, as long as the wire is intact, not cut; the spark is not jumping out of the wire from a knick or cut or anything obvious….it will just appear to be a normal spark plug wire. What I can tell you is that spark plug wires have numbers stamped on them from the factory. Parts 007


When I see numbers stamped on spark plug wires it’s a pretty good assumption that they are the original spark plug wires. If you are experiencing an engine misfire and suspect either spark plugs or spark plug wires as the culprits I would replace the plug wires if you see these numbers stamped on the wire and they have more than 50,000 miles on them….replace them.

Austin Davis

About the Author:

Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."
  • Austin Davis

    Mike, you are more than welcome glad to help.

  • Mike K

    Mr. Austin Davis

    I just want to thank you! I was looking for the answer to this question everywhere. I even called the Ford dealer. They did not know! I been looking for at least 3 weeks. Just ran across this page last night. My 03 Taurus had the numbers on them, I just bought the car. Had misfire and I did not want to just through money at it. They never changed the wires. in 10 years! Thanks a million. Peace