recently bought a B5.5 2.5 TDI Quattro
Firstly I removed the turbo elbow and did the old "mr muscle" cleaner in and moved the vane actuator, car seemed to be a little more responsive, ive got a flat spot now, seems to be around 2500/2800 - 3100/3200 rpm, pulls fairly cleanly then flat, then pulls stong again
plugged the car into a scanner today and we got 2 codes, 546 and 575
the first one seems to be something to do with the connection between scanner and car, the second comes up as the MAP sensor
so i took the MAP sensor out of the NS intercooler (what a PITA!) snapped one of the screws! devil of a job getting that out!!
cleaned off the MAP sensor with some brake cleaner and put it back, not sure it its done anything really, still seems to have a flat spot
any body else had this or suggest anything else it could be?