banzai510(hainz) Posted September 8, 2011 Report Share Posted September 8, 2011 swap another L head and see if this miss still acures. then youll know Quote Link to comment
Sealik Posted September 8, 2011 Author Report Share Posted September 8, 2011 First thing you need to know now is which cyl. it is. When is the miss the most noticable, low, mid, or high rpms? Correct....hard to tell what cylinder when all the plugs are the same....and no anomalies in compression etc. Can't really notice it driving around under load....just at a stop light...engine and shifter is shaking. Rev it up to 3500 RPM ....still missing I usually checked the plugs after a run..which were always clean..but...today I checked after the engine idled for about 10 mins. Found it.....cylinder 2....soot on plug Question is why... This may seem silly, but did you check or replace your spark plug wires? If you hook up a scope to it, you can see where they drop off if they're compromised. Even new wires can have a bad lead. Rare, but can happen. New plugs and wires and cap, plugs gagged at .031. BPR6ES Checked resistance from inside cap to spark plug boot.....well below recommended (to replace) levels swap another L head and see if this miss still acures. then youll know If I had 1...I might be tempted. Since the head (engine) checked out with a compression and leakdown test....no inclination at this point. Would assume the soot on plug is from a vacuum leak???? Engine cold...misses real bad with low vacuum/higher A/F readings on gauges. As engine warms...metal expands choking vacuum leak???? No clue....just a rambling hypothesis... :D But....sprayed WD40 around intake 2....no difference in idle. Also no change in idle with propane. IM bolts are tight....IM gasket has been replaced. Quote Link to comment
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