I am a new member here and I own a 2005.5 Audi S4. I was driving, and all of the sudden, my car started to almost lose power. The RPM's rose as I tried to accelerate but went no where. It periodically did this and then would kick back in. My friends and I pulled over thinking it may have been a flooded cylinder or something like that, but I think we ruled that out. The engine noise would go up and down like I kept lightly tapping the gas. Also, while sitting at a red light, the RPM's would go up and down, as if I was lightly revving my engine. The engine light decided to come on after driving it back home a ways, and then the traction control light came on, and I could not turn it on or off. The traction control light went off after a while and most of the problems went away, but it still seems to be a bit jerky and the engine light is still on. From reading other things, it seems it may be an O2 sensor or an MAF sensor? Has anyone had this problem before and/or know what this is? Thank you in advance!