My 01 s4 has been running terribly for the past couple of weeks. My car was shifting hard, whenever u stepped on the accelerater and even shut down on the highway a couple of times. After some research i figured that it was the MAF, so i changed that and the shifting hard and shutting off on the highway is fixed. Now tho when i step on the accelerator sometimes it runs smoothly and others it kind of spits and sputters like it not getting enough air. Could this be an o2 sensor? Then this morning when i started my car, it sounded like it was going to stall, like a car would on a cold morning. Anyone know what this possibly could be??? I just bought this b5 and love driving it but i can only get the car to run nicely for a week, then something else goes wrong...is any other 01 s4 owners with 108000 having the same problems??? Any suggestions, comments would be apprectiaed!!!