Originally Posted by RS 5tu

first i would check the turbo, take the boost pipe off and check the shaft has no in and out play, there should be a bit of up and down play.
if you can feel it move in and out then its knackered and you need a new turbo this is probably as good a time as any to do a compression test on your engine to see how things are.
once you have done that you will have a better idea of what to do next.