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Spark plug wire fell off

2684 Views 8 Replies 4 Participants Last post by  RayVoy
My 99 5.7 K1500 started running like crap, 2 days ago. On the way home from work my CEL came on so I scanned it when I got home, misfire in cylinder 7. Went under the hood and the spark plug wire had come off the spark plug. The wires were new 16 months ago so not sure why all of a sudden I’m came off. It snapped on nice and tight and wasn’t lose.....BUT the truck is still running like crap. Nothing is showing up when I scan it. Should I assume that spark plug is crapped up now? Or could the wire be bad if it arched while it was popped off, it was only driven about 6 miles in this configuration mostly at 30mph.

Also I am getting backfires on deceleration.
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If it's cold at night where you are a neighborhood cat might have got under the hood looking for warmth. He might have been all over the engine so take a look for anything else he might have disturbed.

I guess it's possible 6 miles was enough to affect the learned tune offsets but not very likely. You can try disconnecting the battery to zero those out.

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