If you were still running the 2wd TPS with the level 8 ecu then at WOT you'd have no WOT multiplier working. Not all mapping uses a WOT multipler, but most do, and typically it is in the region of 10 - 20%. If your chip was mapped as such then at WOT you were likely running 10 - 20% lean. (since your 2wd tps was giving the inverse signal of the 4X4 )

You should have noticed the incorrect TPS though as your idle speed contorl valve would have been inoperative, and at cold start would have been very apparent that the car started badly.