I have a turbo 2000 uk model on a Wplate, im told they boost to 1.1 bar as it has been doing until this weekend.
When accelerating the gauge moves back and forth around 0.8 bar up to 1.5 bar, and you can feel the cars power on and off. Not like its shutting down it does it gradually.
I fitted a new boost control valve about 2 months ago when it was boosting up to 0.5 bar that sorted out that.
I have cleaned out all the boost vaccum hoses,t-pipes and fitted new clips.
Have had the intercooler off and checked all the pipes are ok and tight.
Disconnected the boost gauge and you can still feel it in the performance.
Has anybody had this problem or knows any other things i may have missed,would like to get it sorted as it is a pain to drive.
Many thanks

 

Your Boost Solenoid needs cleaning, its fitted to the drivers side inner wing onto your suspension mount under the bonnet, under a black piece of plastic.

Remove it and give it a clean with Brake cleaner or any good de-greaser, re-fit and away you go.

Zippy