So it looks like i've finally resolved this issue after some advice from a member of another forum. He suggested that it was probably spooling up too quick, so I set the needle valve back two settings and everything is fine again. I can't believe it was such an easy fix, and it never occurred to me that would be the problem as the setting it was on had been fine for a year and I still can't work out how the increased spool rate could cause the boost gauge reading to drop to zero...... Also, the car never went into limp mode when it happened (well by that, I still had acceleration, but the engine just sounded alot rougher). Anyway, if this happens to anyone else, there is an easy fix!
Cheers, Matt.
