Turbo stops working, when ever it likes...? HELP

[lostdog]

I’m having a worrying problem with my Vectra c 2.2 DTI......please help.

Problem:
At times the engine management light will show on the dash, and then my turbo cuts and and stops working. Very Sluggish. Then after a few seconds or minuets. The light will go off and the turbo will start working again. There seems to be no pattern to this and reason it will flash on and off. AT ANY TIME????

Fixes I have tried:

I have check and pushed all turbo vacuum pipes firmly in place. No signs of wear or damage. Checked all levels oil, water... Looked for signs of damage in the engine bay. All seems normal and not changed.....


Does anyone have an idea what it could be?

Thank you