It's a 4l65e and i have just reprogrammed. It actually shaved quite a bit of my 1/4miles, but the tranny hesitates shifting in to 3 at WOT. It kindda stalls for a split second, and then shifts up into 3. The old calibration didn't have this issue.

Does anyone have any ideas as to what is wrong with the calibr. ?
I have set the shift at 6200rpm!
Dunno if it matters but the engine is mated to a LS2 engine

 

No input?