i own a S4 TII. about two weeks ago on the way home from work, i decided to have a little fun, so i was boosting. not excessive boosting, just a little (5psi). i got up to a red light, and it almost caught me off guard.

i had to downshift into 3rd doing about 80kph/40-45 miles. after i got home, and shut the engine off, i heard a 'beep' it did it for a while. i dont have an ecu scanner...so i figured one of you have had this problem before.

well, now, my car is reluctant to move. i have an air/fuel mixture gauge...before that nite, it used to jump from lean to rich while i was driving. now, it just stays in the middle. it stays in the middle from about 2000-2500, and sometimes when i'm just going the speed limit on the streets. please note that when i use boost, it does react normally...it's just when i'm not using boost that my FC feels reluctant to move.

this happened after the fuel cut happened several times during since i put on my new exhaust. can this be linked together? what should i do?

any help would be much appreciated