hi my 1998 1.9tdi ahu engined audi a4 is pretty much broken. problems started with once you got to 80 miles an hour or there abouts there would be a thud like hitting the rev limiter and the turbo would turn itself off, ie. there was no more pull at all even when changing down gears or at lower speeds. turning off the ignition and restarting the car seemed to solve this untilyou hit 80 again. i lived with this for a couple of weeks as i was too busy to look at it, now it has progressed to there is no turbo at all, as soon as you hit where boost should be the car splutters and struggles and generally it will not rev past 2000rpm although 3000 can be achieved in neutral. im in the process of servicing the car to see if that helps, doing the fuel filter oil and air filter. besides maybe a dirty fuel filter im suspecting the turbo has blown which would be surprising as there isn't any real smoking and it's only done 113k can anybody offer any advice or suggestions to the problem? cheers chris sorry also forgot to mention since the problems have started my engine temperature goes up and down whilst driving the car, it can vary from as low as 65 up to just under 90 which used to be normal but is now on average settling at 70.