This car came in with a small lack of power. A code read gave 3 codes relating to boost pressure and one to glow plugs. We stripped to gain access to the turbo but no faults were found with the turbo, exhaust,vac pipes, solenoids, boost pipes, or intercooler so we rebuilt the car and erased the codes. We were then informed that the local dealers had fitted a dozer unit a month ago (Oh, wouldn't it be nice to have all the info available at the start), we assumed that the boost fault codes were caused by a vacuum fault on the old dozer and the codes not erased. We also cleaned and checked the egr and tried a maf sensor on it. The only recurring fault code is glow relay, all live data suggests ok.
We also have a 'whooshing' noise on full acceleration, but if you ease off the throttle and accelerate again the noise goes and will not come back until you change gear! The noise would suggest a vac/boost leak but there isn't one and if it was a leak it would come back before you had changed gear (you can stay in third gear for ever and it does not come back).
Anybody any suggestions? The lack of power is only small and the car is driveable but the customer wants it fixed and they are always right!!