View Full Version : 2005.5 audi s4 will not go over 4500 rev

08-10-2013, 09:48 PM
i just got my audi s4 05 b7 but the car will not go over 4500 rpm when driving it, it will go only over if i accelerate gradually if i step on it fast it will choke i changed the fuel pump, the fuel filter ,spark plugs,coils,mass air flow .some please tell me what could be the problem even civics are blowing past me [=(]

08-24-2013, 12:21 PM
I'd start wondering about the cats choking the engine.

Back in the early 90s I had a Camaro with a clogged cat. In the end I could drive it only at lower RPM and very carefully as the cat was in very bad shape. Exhaust shops used to be able to do a pressure differential test on the cats by drilling small pilot holes in the exhaust and measuring the pre and post cat pressure to determine if it was clogged. I don't know if they still do this with the newer ODB systems that monitor the cat efficiency.