Here is the background on my '09 CTSV. I lost 4-5-6 in my 6L90e so I bought a reman. from GM. While the car was down I decided to do a mod or 30. So I went with a forged 427, WCCH ported heads, GT9 cam, SW Exhaust cat delete, 102mm TB, Ported Snout and Blower, overspin the blower with 2.55 upper/9.1 lower.
I got the car running about a week ago and Ed Hutchings has been helping me tune it. The first problem was that the TCM from GM had no tune and was stuck in 3rd gear. Took it to the dealer and they flashed a new tune. It then shifted and seemed pretty good. There was lots of hesitation and rough running at part throttle, but each tune Ed sent seemed to make it better. At WOT it felt really strong other than a hiccup or two which also went away with each new tune.
The only real concern i had was the fact that when I put the trans in sport mode and manually downshifted, sometimes it would run like its firing on 5 cylinder and then clear up after a while. When I logged it and sent it to Ed we were suprised to see the timing drop to -10 when that condition occured and stft would go to 0 and stay there. This only happened every once in a while and I hardly ever used sport mode so I wasnt too concerned.
I took it to the track last night and it didnt know whether to sh1t or go blind in 1st and 2nd. Once it got into 3rd and 4th it ran good. I never launched froma standtstill on the street so didnt expect this at all. I would punch it from 20-30 and it would drop into 2nd and then run out real strong from there.
The file I am attaching now shost the downshift issue starting at 00:03 seconds in. I am sure this can be figured out and look forward to getting it resolved. Thanks.