I don't think this is the right place to be asking those Jetta questions, there are a couple of really great Jetta TDI forums that have thousands of questions and solutions to your 2006..
Google them if you still own the car, (if you do, get rid of it) join up and use the "Search" buttons. You will find owners have found lots of easy fixes for what seemed to be expensive trips to the dealership, questions.
The 2006 VW Jetta TDI is now an orphan in the VW line up, the BRM engine has been replaced in 2009 with a more reliable fuel injection system, a better 'top end' design and 35 more Hp.
But wait the 2011 is due out this fall and will be a total re-do of the 09' model.