My car has been acting funny since last October 2010. The car doesn't hold boost properly. You can really notice it in 3rd gear. You shift through the gears and it holds boost and then all of a sudden it will lose boost and then rev up again and repeat this over and over. It can't be the clutch slipping because the car wouldn't be going anywhere and would just be revving. The car gets really bad when it warms up. Dealership thought it was a leak in the piping fed into the turbo, but that's not it. It's still doing it. What is it?!?!