hhmm...I wouldn't only call one mechanic and trust what he says, especially if what he says lines him up for a job of $200 - $300 at least. I guess the easiest way to check would be to jump back in your car, warm it up and then go for a fang - if it gets on boost, then it's working, if it says well under 0 manifold pressure then it's obviously not making boost and wheel very well may have fallen off.