Hi, Im after some advice. I purchased a 2002 A4 Avant Quattro 2.5TDi over the weekend - its only just become apparent that im not getting any boost from the car. I can hear the turbo spinning slightly under light acceleration from about 1000-2000rpm, after that there is no turbo sound even when I put my foot down. Im just wondering where I should start with this? - I have ordered a new N75 valve (I had one go when I owned a 1.8T) as I figured it may be a good place to start. I have scanned the car with VAG-COM - the only error I got was; 00542 - Needle lift Sensor (G80) 30-10 - Open or Short to Plus - Intermittent I know this is an issue with no3 injector - but the car runs fine - no smoke, no rough idle - would this fault cause a no-boost situation? (the engine management light is not on the dash) I have found the following diagram - N75 is top left - im taking it numbers 12 & 13 are are also valves - is it common for these to go? Many thanks!