Last night I changed the fuel pressure regulater, so going in this my expectations were high, and the heat race and the problem was still there. just a litte frustrating. My team-mate v grooved the pick up hose in the fuel cell and I think that helped, it had stumbled only twice in the main not 5 times like the previous race. I had a wire melt the insulation and break that ended the night with 1-2 laps to go while I was running in second. I love the ideas and appreciate the suggestions.
David Peterson

 

I know this may sound stupid, but that problem sounds like it could very well be the spark plug wires. Regardless if they are new or you already checked them, it could be something inside and you would never see it. Try swapping them and see what happens. I had this problem once with a car I owned and I went through everything you did and then someone made this suggestion and then I was like: Well I'll be damned. I can't believe this shit...