Well, the gap sounds about right. If it revs past 4000 on light throttle, just cruising it to the upper RPM range then I still think it's spark related.
If it won't rev past 4000 at all, then I'm going to guess that the ECT sender is playing up and the cold engine RPM limiter is kicking in. Get a log and post it up so we can have a look at what is going on.
Simon
I asked for this a LOOOONNNGGGG time ago... Response... When V8 comes out.
"All that is needed for the triumph of evil is that good men do nothing..."
I wondered that as well; but I decrease KR sensitivity, increased KR recovery rate and I am now getting sawtooth patterned KR so I think it's legit and I need to soften the timing. Also, 2 months ago when I began this I used stock GM timing table and had no KR, although the truck was way down on power. I am wondering if the timing is legitimately too aggressive in the mid-range... I think what I will do is use the bi-di controls and do WOT pulls in 2nd gear to eliminate gear changes and see what the KR result is.
Mr. P.