Hello all. I purchased a 2001 S4 about a month ago, 59,000 miles. I have been having an intermittent problem under acceleration that hopefully someone will be able to diagnose. In 2nd sometimes and 3rd mostly the car hesitates under accelleration, surging around 3k-4k rpm, then taking off. In 3rd gear this is usually accompanied by a CEl, that flashes at first then either stays lit or goes away, it doesn't seem to be consistent. As far as I know, the car is stock. There is a AWE boost gauge in the vent, but the diverter valves and TBB look stock. I don't know about the computer. This is a really annoying problem as it leaves me with little confidence in the car. Please help. Thanks.

 

That post didn't make a whole lot of sense. When I had my WRX I had a similar problem when we replaced the IC. The car would boost until a certain PSI, then just surge and feel like it was dragging. The S4 does the same thing but the boost picks back up.

 

Someone else has to have had a similar problem or an idea. Are the above symptoms related to the Throttle Body Boot? The diverter Valves?

 

my '01 does the exact same thing. i have been searching all over different forums trying to find someone else who had that problem. i was told that it could be my TBB so i checked it and it was blown so i replaces it with a silicone one thinking that would fix it. it didnt. i have hyperboost DV's so it is not them. then i was told that i could have a bad fuel pump so i replaced that too, still didnt fix it. i thought it might be aboost leak somewhere else so i got a full silicone hose kit when i got my turbo upgrade and was sure that would fix it, but once again i was wrong. the best i can figure is that it is my injectors. i got the stratmosphere stg. 4 so i still have my stock injectors. i havent done anything about it yet but it is drivng me nuts. if you figure out what the problem is make sure post it soon.