Well I was to get my car re-tuned today, put it on the dyno everything seems normal simon gives it some and it starts spike boosting then goes low and then back up and it ends up like an endless wave. We were stumped as to why it was doing this, first we though there was a boost leak, checked everything - re-tightened a few brackets, round 2, still the same.. Thought it might have been the acuator, nope not that either. We took a look at the boost sensor to see if its not connected properly etc.. It's all perfect, nothing else could be wrong. The only thing we could think of being wrong is the boost/map sensor might be fualty.. So tommorow I'm back off to simons to check to see if that's the reason for my car's abnormal behavoir.. if it's not the reason then I have no idea at all.. Has anyone else had these similar symptons before?