lost boost

[yourloveismydrug]

2003 GT tdi 150 driving up the road and I put my foot down in 3rd gear and all was well until just after it started boosting and then it went flat.  No boost .  no lights on dash , no noise , no dramas ( other than the Mrs saying ' thought VWs were reliable') .

some black smoke was noted earlier from the exhaust , not loads but enough to be noticeable .  would suggest a leak in the boost system .

ideas , where to start

[Adam]

It sounds like limp mode. Get it scanned for faults.

[yourloveismydrug]

I canned it when I got home and nothing , not vagcom or vcds though 

[Adam]

If it was limp mode it would have stored a code. Check the boost piping and the vacuum piping on the bulkhead.

[yourloveismydrug]

I check all the piping , got under the car and checked everything best I could .

ran all the diagnostics software I have , cant find my vcds disc 

took it for another run and its fine .

could I have a sticky turbo ?  would that lodge fault codes ..  what to do if it is , cleaner etc .

[yourloveismydrug]

took it out for a drive , a brisk one and  no problems .  so as soon as I have a minute or two I will be going over all the piping thoroughly and having a look at the turbo etc