TDI lack of power

[Mk2 Forever]

My friend recently brought to me a 2000 130Bhp Passat Tdi with a severe power problem. On investigation the vehilce would not accelerate above 3000rpm. Having read several other threads regarding this i changed the MAF (Mass air flow meter). The vehilce now continues to accelerate past 3000rpm, however there is no urgency, it feels almost as if there is no turbo assistance. I have stripped off the accillary items and witnessed the turbo rotating, i have checked its play and its tolerances seem fine. However i cannot check the performance of the turbo under load. I am not convinced the boost control system is operating correctly. How do i check this, is there a common fault i am missing. Whom would you recommend i return this vehicle to for accurate diagnosis, VW never got off the blocks and denied the original fault ever exsisted....Any help is always gratefully recieved.

[devonutopia]

Get an independent scan done of the ECU using vag-com / snap on fault code reader. Something should be up so a fault code will have been logged. If you've swapped the MAF, next point to check might be the boost sensor in the intercooler. if that gets dodgy, it cuts out turbo boost but should log a fault - usually called "thrust sensor" by dealers.

[Mk2 Forever]

Independant garage hooked it up to the fault code reader, and yes the turbo boost control system has registered as a fault. They cleared the fault from the memory and the vehicle now performs as it should, quite powerfull but doesnt handle with anywhere near the same precision as my Mondeo zetec S. Moral of the story, change the MAF and then clear the fault memory. Thanx to the forum for all the advice.