running ofab on a zetec turbo. just running in just now. sometimes on a cold day itl boost to 9 psi ish and it hits what i think is a boost limiter type thing. once it has done this it wont boost. coughs and splutters etc. if you switch it off and restart it, it cures and its back to normal. boost is set with a bleed valve. no amal valve fitted.

does anyone know whats going on.