The truck is a 08 Sierra 1500 2wd 5.3 4l60e stock. I tuned it yesterday and went test drive it everthing went well, but I will not shift a full throttle from 1st to 2nd, it feels like a it's a fuel cut off but I cannot find anything that would cause this. Shifts are set at 5900. This is the first 07+ truck that I tune so I could be missing something. Also at full throttle the truck only shows 83-84% tps in the scanner.
Any help is appreciated.