It only does it in 3rd and 4th gear and only while racing. When I shift the hell out of it it just collapses and has no power and the car starts sputtering, if I shift slower it runs absolutely fine. I thought that it may be due to the gaping hole in my lid, but that has been replaced and it still does it. I've noticed it doing it ever since the car was dyno tuned....any guesses? The car has been unraceable for 2 months.