chris38

I have a 2000 A6 2.7T with 55,000 miles. Lately, upon light-to-moderate acceleration, I'm experiencing a hesitation. It is sort of a fluttering, bucking sensation, like it is building boost but then the boost gets cut, over and over again. This problem is gone under WOT, however. I had the car at a dealer last week, and they did a brief diagnosis and told me that it might be that one of the wastegate solenoid valves is sticking. This doesn't make much sense to me, especially as this happens several times during a part-throttle 20-60 run... Does this make sense to anyone? What about a torn throttle body boot? I just installed two new HyperBoost Compact diverter valves a couple weeks ago...

BTW...the car is also for sale, if anyone is interested. Except for this issue, it's in very nice shape. 55K, 6-speed manual, BBS wheels, immaculate interior, Ming Blue Pearl Effect.

quickaudi:STFA

did this hesitation coincide with the install of the new diverter valves?

chris38

Originally I had the car at the dealer because the MIL was on...after taking the diverter valves apart, they said that one of them had a torn diaphragm. I told them I would replace them myself.

When I picked the car up that night, this "bucking" sensation was BAD--almost throw you forward in your seat bad. It got much better within a day, however, and the symptoms have more or less been constant since then (even after I replaced the diverter valves). Lately it seems to be fluttering more quickly (and more often) during a part-throttle acceleration run than before. Hope this helps.

quickaudi:STFA

torn diverter valve, then it's fairly likely that something else has torn as well.

chris38

They did a leak test at the dealership and said everything was ok...

quickaudi:STFA

search the S4 Wiki for ways to test the N75.