Why change plug wires when changing plugs?

[mikeh]

So I'm at 90K and getting ready to change my plugs out. Do you think it's really worth it to change out the plug wires while I'm at it? I don't know anyone that does this. Would this be part of a regular maintenance by Ford if I took it in for 100K tune up? Do you think I'm better off just checking them and leaving them on? I would check them by running the engine at night and wiggling the wires and seeing if I can see any spark from grounding.

Motorcraft wires at ORielly are $53. Is this just being cheap not replacing them? I'm on the fence as I've never had a problem caused by bad plug wires.

 

[Dan Whitaker]

Yes ford would replace the wires on a 100k service. Just because they wires don't spark doesn't mean they are good. When wires get old they build up reisitance. This is measured in ohms.

It's easier to replace them while doing the plugs than later. That $53 you want to save now could cost you a lot more in lost milage if you don't change them.

 

[1_v8_merc]

You don't have to, the wires could still be perfectly good.

It just depends on the individual vehicle.

Some people need to replace wires at under 100k, while others dont need to till 130, or 150k.


I never replaced the wires on my mustang till I hit over 130k...and i DIDNT even need to do it, I just had cash laying around, got bored and decided to do it....putting new wires didnt make it run any better....even at 130k.