Hi, the turbo may be working fine, the problem is either the gauge is no good or you have a vac/boost leak somewhere... you you should do a pressure test on the induction system, or take all the induction & vac pipes off for inspection or at the very least check all the connections and have a look for breaks, cracks & splits. try a different boost gauge first, you should be able to pick one up cheap from ebay... if that does the same thing then start on the pipes.