I have a 2002 TDI with 310,000 miles with an overboost problem. Using vag-com I see a pretty consistent pattern where the actual boost is greater than requested. In the higher gears heavy acceleration above 3000 rpm causes it to go into limp mode and occasionally throw an intermittent overboost code. I've swapped the N-75's but the same pattern remains. The intake was cleaned 30,000 miles ago at the last TB change. I've replaced the vacuum lines, EGR and MAF recently. I've checked the accuator operation and it seems ok, moving with very little vacuum and snapping back without obvious sticking. I'm the only one to work on the car since new so the turbo linkage has never been adjusted. The thing I'm having a hard time understanding is the fact that the overboost so cleanly tracks the requested but the trace is just higher. If the vanes were sticking it seems like there would be a noticeable delay where the actual remains high while the requested falls off. But this is not the pattern that I'm seeing. Anyone have any theories about this and how to fix it? I don't want to buy a new turbo and then find the issue remains. BTW it doesn't seem to effect the mileage or driveability, until it goes into limp mode.