I have been reading this forum for a while and it's time to ask for help.
We installed an LS2 w 4L60E from a 05 GTO in a 91 Z28. We had speartech do the harness for the conversion and it's a stock drivetrain with headers.

Now the problem, WHen you go past half throttle in low gear the computer will not let the throttle open more then 40-50% after the car shifts in to second gear the throttle opens all of the way and the car will rip! Jessie at wait4me has been a great help to me but I know he has to be one of the busiest guys in the planet so I hate to bug him.
I have the traction control disabled and have tried many things in the engine and trans tune with no luck. Any input would be greatly appriceated.

Jason