Hello everyone! I've been reading through several DIY's and troubleshooting my 2006 TDI (135,000 mi) for over a month now. The resources available here are truely endless and a great place to get to know your vehicle and save some mechanic cost in the process.
My Story:
I managed to find a bad tank of diesel which clogged my fuel filter and make the car run poorly in a matter of miles. This not only clogged my filter but it also degraded my fuel pump and damaged an injector. I replaced the fuel pump and filter and completed drained an wiped the tank clean. In the process I found an exhaust leak in the ERG cooler, so I while I was at it, I replaced this as well. The injector was then replaced by the local VW dealer :/ and the car continued to run poorly under a load (and/or boost condition). After 2 days of talking with the VW Technical Help line the dealer diagnosed the problem as the turbo was faulty and needed replaced. I'm working on running some of the measuring block test to confirm their findings and verift the actuator isn't stuck or something else.
Thanks for all of the great information, I will keep you guys posted with my results.