How Often Do Spark Plug Wires Need to Be Changed?

Spark plugs provide the electricity necessary for combustion to happen by igniting atomized fuel in an engine's cylinders. However, they need a constant supply of electricity to do that. This is the job of your spark plug wires. And, just like your plugs, the wires wear out over time. Once they begin to wear, the electrical charge sent to the spark plugs can be unreliable, which creates problems with engine operation, including rough idling, stalls, and other issues.

How often should you change spark plug wires

There’s no single rule that governs all vehicles. For one thing, your car might not actually have wires – many newer models don’t. These models use a coil on the plug instead, and coils can last a very long time. With that being said, modern spark plug wires can also last much longer than they once did.

Most of the time, your wires should last well beyond the 30,000 miles your copper spark plugs are rated for. However, there are other factors that can play a role in the timing.

  • Damage: It’s possible for spark plug wires to be damaged. If the insulation is compromised, or there’s an internal break, you’ll need to replace your wires even if it’s not yet time.

  • High Performance: High performance doesn’t always mean a long lifespan, and some types of high performing spark plug wires may need relatively frequent replacement (every 30,000 to 40,000 miles).

  • Increasing Resistance: Perhaps the best way to tell if your spark plug wires need to be replaced is to test their resistance. You’ll need an ohmmeter for this, and you’ll need to know what the wires’ original resistance was. Test each wire and look for resistance levels higher than when originally installed, as well as higher resistance in individual wires (which indicates a failed wire).

All that being said, the best option is to follow your mechanic’s advice about replacing your spark plug wires. While modern cars don’t need the regular tune-up service that carbureted cars did, they do need regular maintenance, and plug wires do eventually fail.


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Michael

4 years of experience
230 reviews
Michael
4 years of experience
Chrysler Town & Country V6-3.8L - Ignition Cable (Spark plug wires) - Noblesville, Indiana
he tried everything he could to find out what was wrong with my car, and, unfortunately, was unable to find the cause, but he tried all he could.
Ford F-150 - Ignition Cable (Spark plug wires) - Indianapolis, Indiana
Michael was very professional. He arrived on time and got right to work. Finished the job ahead of schedule .

Pardeep

21 years of experience
1068 reviews
Pardeep
21 years of experience
Chevrolet C30 Pickup V8-5.7L - Ignition Cable (Spark plug wires) - San Jose, California
I have an older Chevy Pick Up that needs a little extra work to keep it running. Pardeep keeps me on the road.
Mazda Miata - Ignition Cable (Spark plug wires) - Cupertino, California
Very impressed by Pradeep’s expertise and professionalism. He was able to quickly diagnose the start problem with our 96 Miata and replace the faulty cables. Explained everything in detail and provided good quote and estimate. Overall, a very pleasant experience today!

Stephen

32 years of experience
178 reviews
Stephen
32 years of experience
Ford E-350 Econoline V8-7.5L - Ignition Cable (Spark plug wires) Replacement - Westminster, Colorado
Stephan is a pleasant gentleman. He did the job I needed and recommended I get some other work done on the vechicle. The only thing I didn't like was he was 15minutes early.

Larry

16 years of experience
114 reviews
Larry
16 years of experience
Toyota Camry L4-2.2L - Ignition Cable (Spark plug wires) - Columbus, Ohio
Larry was great and a great mechanic was very polite I would recommend him anyone who needs a mechanic I would recommend him to anyone

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