I have the following problem: TT turbo seems to operate intermittently. Some mornings it will not have any boost (no turbo whine...)... and feels like an everyday average car...then it will start working (say after 30 min drive and 1 hr shutdown) and go like a banshee... anyone else have intermittent turbo boost and what can be done to diagnose? The dealer is NO help whatsoever.

 

Do yourself a favor and get a REVO tune! http://www.revotechnik.com
Best bang for your buck mod as far as a performance enhancement goes for your Turbo TT.
I got Revo'ed and the difference is like night and day!! The boost comes in a lot sooner and
it is a lot more powerfull in the midrange all the way to the top. Smooth, seemless accelleration.
No Turbolag whatsoever. I also went with their optional SPS3 switch which lets you fine tune your
cars performance and adjust Boost and Timing. I have it set at 6 for Boost and 5 for timing. Runs like
a Banshee. You can also set it for generic settings for 89 Octane, 91 Octane, 93 Octane and 100 Racing Gas.
It also offers a Anti Theft mode where when set it wont allow you to start the car even with the key.
Very nice and well worth the money. With the Revo Tune an aftermarket Diverter Valve would be recommended.
You actually may have a defective DV and that's why your Turbo feels like you describe it. Go with a Forge DV.
It doesn't leak like the stock ones tend to do and are made out of metal instead of plastic.
http://www.ttstuff.com/performance_turbo.php

The DV is very easy to change, so you might try that first and then go with the REVO tune.