Just thinking out loud, I'm wondering if a badly worn guide/valve stem/seal is letting the plug, oil foul almost immediately, the compression would still be good as would the valve spring. when you put the new plug in there is it still running rough IMMEDIATELY? (before the plug has time to foul) If so I might be wrong but I keep thinking a "balancing issue".
I’m just not seeing where the balancing could be off and why that would be affecting the number 8 plug?
Like I said i have crawled under the truck and removed the converter inspection plate and verified that it is a weighted Magnum converter.
And a La style flex plate.
The engine still has the balancer on the front that came with the engine from Mopar.
And the number 8 plug isn’t oil foiled, it’s fuel.
This just doesn’t make sense to me, but I have a strong feeling the rough spot I’m feeling is connected to what’s going on with cylinder 8.
Would it be a good idea to have the engine hooked up to some kind of monitor to watch the spark events to see exactly what’s going on?
There has to be way to determine whatever is going on here.
