Ran into a weird problem. 2001 Silverado 2wd. Has a 4.8l /Turbo. We did a 4l80 swap into it,switched the wiring and switch the tranny calibrations to a 4L80. Truck runs great,tranny works awesome but under boost the truck drops to the minimum spark advance .I've gone over and over the tune and find nothing.Before the swap it ran full timing,no problem.

Has anyone ran into this before?I'm out of idea's. Got the tune if someone want's to take a look.

Thanks