07 Silverado PCM, TH400 swap, 2 Bar OS - Loss of Pedal Control in Boost

6l swap in an 80's Malibu. Customer called indicating after tuning at a shop local to him he had loss of throttle when making boost.
Replicated this on our dyno. When the car makes approximately 8psi the throttle goes dead.
Does this require a manual trans cal? I did try disabling all the trans codes that came up but the issue persists.
I also tried various other parameter settings I found searching the HPT forum but nothing seemed to correct the issue.

The attached tune is where we gave up trying various settings I found - so go easy on me please.