I think I found the miss

2007 Chevrolet Silverado Classic 1500, 5.3 engine, 210k miles. I thought I was feeling a slight miss in the engine. When I stopped for gas, I opened the hood to check the oil and noticed this, the # 5 spark plug wire was up against the bolt on the steering column. I rotated the wire at the boot 180 degrees to get it off the bolt. The insulation is definitely worn down where it touched. No CEL or codes.


Good work finding it. It feels good to find a clear reason for a problem and fixing it.

Definitely good diagnostic work there. I had a similar problem on my 45+ year old Ford truck last summer. The problem was the transmission shift lever was hitting the wire, thinning the insulation over time. I just wrapped the bad spot in several layers of Scotch 33+ electrical tape, which fixed the slight miss straight away.

Yeah I had that happen too but touching a different part.

yeah, good work. But either replace the wire or wrap it with good electrical tape.

Nice logical work, starting with the basics, with an eye for detail. Gus Wilson hires guys like you! Thanks for reporting your results.

If the spark was arcing to the steering column then you really need to consider the spark plug condition.

An aged plug or one with a large plug gap can cause an arc where there might normally not be one.

That’s a good point but it appears the constant abrasion from the rotating steering shaft bolt wore away some of the insulation…

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Agree, since the truck is new to me, I plan on doing all maintenance items since it didn’t come with a maintenance history.

Only the outermost part of the jacket is worn. I was thinking of just replacing the wire or wires when I do the plugs but that alone won’t solve the problem. I have some loom jacket that is just slightly larger than the wire and am thinking of getting a tube of RTV silicone. I’ll wrap a section of the loom, about 4" in the area abraided and fill the space between the wire and the loom jacket with the RTV. I can hold it in a straight line for awhile, or put a temp brace on it and when it cures, the wire should stay well away from the steering column then. I’ll post a pic when I get it done.

We had a technician wrap one plug wire with electrical tape, the miss fire driving home turned onto being down a cylinder the next time the car was started, 3 out of 4 cylinders on a 1990 Mazda protoge doesn’t sound that great
We got a new set of wires for free the next day.