Car runs great otherwise, but seemed to get significantly worse after going SD tune. Car is an 06 GTO, A4, Texas Speed iron 408ci, PRC 245cc heads, T-rex cam, Fast 102 inyake, NW 102 TB. I've been through the tune quite a few times, can't find what might be causing this other than the TB is so big it let's too much air in too fast and the ecm can't get fuel to it fast enough? Only does it when you slam it to the floor, wideband says it goes completely lean, about 1 sec then fuel catches up and works great. Anyone else ever had this problem?