you didn't mess anything thing up.
its the down fall of a bigger TB.
Rough Idle and Throttle Hang..
it happened to my Stang when i jumped to a 70mm
at first i went with a MAC one and it was really bad so i swaped it out with a Ford Racing Performance Parts one and it was alittle less noticible at first but as time went on it would become more noticible
