Ok. Could it be the TPS out of adjustment? The actual plenum chamber has been modified to fit in the confines of the engine bay. The runners are now angled at 45deg pointing forward and about 2 inches longer than originally. The engine sits right back in the engine bay with about 8 inches in the car. There wasn't enough room where the pedal box was to fit the plenum chamber so it was bought forward to make it fit.
What could be the issue with the throttle body?