looking on the live data when roadtesting the vehicle on autodiagnos it gives a min and max boost value,the turbo appeared to be overboosting.checked the operation on the one boost control valve and it was fine. put a vac gauge on the wastegate and it wasnt operating,the wastegate was seized closed. removed the turbo and fitted new £425,job sorted. common problem with this model of turbo apparently they change on on "96" early turbo's are reliable model number 454183 late ones suffer from the above fault model number 454183. hope this helps someone. sean