Audi 90 Tdi

[melix]

please help me! i have 93 plate 90 tdi.have some problems been to four garages and had diffrent answers to the problem.
i have severe loss of power first it was just going up steep hills now it got alot worse and only get any speed going down hill! have cleaned air mask meter with great care i must say.changed fuel filter put deisel cleaner in to clean the injectors . so followed all advice to no avail the turbo wnt kick in no matter how high i get the revs got a feeling the fuel to blame somewere along the line.the turbo ok dnt get any smoke starts well.even on the coldest of mornings.so my poor luvvy is sat on drive.
it was very gradual decline in power over a couple of months. please help i fed up of paying garages to spot things that are bloody obvious.
hope you can help as our audi garage didnt want to help because my honey not new.