Was wondering if the spark plug wires ever need replacing?

 

Yes they do. All modern sparkplug wires are suppression or "resistance" wires, to cut down on radio noise, and also interference with the new electronics. The wire inside is not really a wire at all, it's a piece of nylon or some other type of rope or fibers that are filled with a graphite or other conductive carbon-like dust. Over time with vibration, the dust can settle out of the cord, and cause a poor connection, and a slight miss-fire in the engine. That's also why you need to be careful with the wires, the graphite or carbon core is very delicate.

 

Well, I just got new spark plugs for my 2005 Ford Ranger 2x4 2.3L with 66,730 last time I checked. Should I get new spark plug wires too?