ok. i have a 98 audi a4 with 127k miles. i bought the car with one problem. the wastegate was shot and the car hasnt seen boost for who knows how long. anyways it drove great just not quick. a month ago the icm went out and just replaced it yesterday. at the same time i replaced the wastegate and installed a 3" cat delete pipe. when i started it up all ignition coils were firing and the turbo was spooling, but now a have another different problem. it sputters and accellerates rough after 2k rpms, usually when more throttle is applied. i took my a4 to autozone to see what codes it was throwing and found 4 air/fuel codes, 2 o2 sensor codes, and a mass air flow sensor code. any ideas what my problem could be? please help me out. thanks