I am starting to get lots of vw and audis coming in with this problem. Fault code P1557 turbo pressure exceeded.we scanned car with vag-com and Solus. Ive replaced boost pressure sensor.and added fuel additive to help clean turbo vanes. Looses power when 3000 revs are reached. Switch engine off and restart and everythings ok again.checked readings for airmass and all seems good.i did fit a new air mass just to try but still no good. There must be a easy way of sorting this common fault? help and advice would be great.

Thanks