I have an a4 2.5 tdi quattro which has never seemed very fast considering its supposed to be a 150bhp model (AFB engine). I had it vag com'd by a mate last night and the MAF was reashing a maximum of 550/stroke when the engine really needed aroun 800/stroke according to vag.com. I've change the MAF twice now and the latest one was a BOSCH so i think thats ok. I also need to change my air filter which should help a bit but are there any other obvious other things i should be checking given that its down on power? One otehr thing.... the metal link pipe at the front of the car below the bumper which links the two intercoolers together has some rust and possibly a hole in it. This may be causing problems as the compressed air from the turbo could be leaking out before reaching the inlet manifold. Other than what i've mentioned i.e. MAF, air filter, possible leak on metal pipe are there any other common problems to look for whenexperiencing reduced power (its not limp mode and no faults codes came up on vag.com). Cheers.