I changed the front brakes and spark plugs on my 5.0L Explorer this weekend and intended to replace the wires. I bought a set of wires that didn't have enough of the insulation sleeves on them to protect from heat from the manifold so I opted to leave the original wires on temporarily until I buy OEM wires.

So, yesterday on my way home from work the truck starts bucking at around 40 MPH. I didn't sense any noticeable power loss so I was not sure if I was on 7 cylinders or not. When I get home I noticed the longest wire on the left side was arching as it was unprotected (I must have routed in wrong) with no inuslation sleeve. A closer look revealed a burn mark through the wire. I used some electric tape to seal it temporarily but to no avail. I noticed the same problem this morning and the check engine light flashed several times.

At low speeds and low demand, I experience no problems. I assume the low voltage causes no problems through the damaged wire. At high speeds or demand, the truck bucks and shakes.

I'm wondering if I might have knocked off a vacuum hose as well. I plan to change at least the one damaged wire tonight and do the rest shortly thereafter.

Anything else I didn't think of or missed?

Eric

 

Check all of the wires carefully. It's possible that others could be arcing as well. Also, check them all to be sure that they are fully seated on the plug and in the coil pack. Usually a loose or leaking vacuum hose will cause more problems at idle than at speed.