I am the new owner of a 2005.5 A4 2.0T Quattro. I have replaced the diverter valve recently and now notice a new issue. When I first hit the gas, the car seems to sputter a half second or so before going. Also, as I come into a stop the RPMs dip down to 750-800 or so and it almost seems like it wants to stall.

Anyone familiar with such an issue? any guidance would be appreciated.

 

i recently had this "issue" after buying cheap 91octane "premium" gas..
i usually go out of my way to only fill up with 93octane premium gas, but i had a giftcard for $20 at a different station. i dont think my car started to do it until i filled back up with 93, but after about 100miles, it went away.

did you by chance gas up somewhere different than usual just before or after the install? i believe our computers make slight adjustments to themselves for the octane (i think its actually the RON level) to a point.. obviously its not going to adjust for 100octane race fuel. i should also add, when/if you were to ever have your car chipped, you usually choose 91 or 93 octane profiles so it does make a difference in the way your car drives.
and on this topic, NEVER gas up with less then 91 octane.

i dont think your DV would make any difference. i added a forge blowoff spacer and that made no difference in how the car acted, so a new DV shouldn't either.

 

oops...

 

Just had my diverter valve replaced and my car doesn't have any of those symptoms. My car normally idles at 750 rpm, but then my car is a manual. Automatics might idle at a different rpm. The 2.0t isn't the smoothest idling engine. It's also possible that it's just a touch of turbo lag. With the diverter valve bad, you're dumping all the boost, and the turbo isn't providing boost as it spools up, so you won't notice lag. That happened to me. Now I get what I had before, a instant like almost hesitation that's gone almost as instantly. as the boost builds and the car takes off.

 

It seems that it was a fuel related issue. I did use a "cheaper" 91 octane fuel as I was in an area pretty far from home and needed some gas, baaaad.

I have since, filled up twice at my local Sunoco and Shell stations with 93 octane. It is worlds of difference with the correct fuel.

Thanks for all the help!

 

I had the same issue. It was the problem in the cheap "gas"