Ok, so here's what happened today. Coming home from work, got out on the 4-lane and I wanted to wind-er-up.
I stayed in 4th to keep the speed down obviously, don't need any performance awards....
The motor was singing right along easily 6K-7k, I went to back off the throttle, and no reduction. I tried to snap the throttle a couple of times to get it to back off, didn't work right away. I touched the brakes a bit to load it down some, to down-shift, not a good idea........
As soon as I touched the clutch I realized I did an oooops. I let go of it right away, but not before the motor went little-no load speed. I did finally get the throttle to release, but the result was I now had an obvious mis-fire.
It got me home with 3cyl.
I located the cause of the sticking throttle cable and corrected it. A piece of my fuel line insulation became unfastened from the fuel line and was in the perfect position to catch/snag the cruise control linkage. No longer..
Back to the misfire, 1st I connected my carbtune to see if I could tell which cyl I was dealing with, didn't tell me anything. All 4 still showed decent vac, so that was a good sign anyway.
Pulled the plugs, got the 1st 3 out and they still looked like new, pulled the 4th and low and behold there was no gap. Bosch XR5DC
Near as I can tell the top of the piston came up and hit the plug. Got my light out and I couldn't see any damage thru the plug hole, ran a compression test, came back good 185+.
So I re-gapped the plug, put it all back together, and it fired right up as if nothing was wrong. Took it out on the highway again, ran it up to 7K+, no problems. So I'm not sure if it was just a fluke that the piston tapped the plug, or if it's a sign of excess piston travel to be concerned with, or possibly just a layer of carbon buildup on the top of the piston.
Thoughts?
Oh, btw this was the '97 with 49K miles.
