abrupt off boost pwr loss

[Paulofolympia]

Recently had some work done. New clutch,throw-out bearing,cleaned up throttle body,throttle position sensor,valve cover gasket,rear brakes,pwr steering pump,various vacuum lines. Whew! Running very well- daily driver w/180k miles. A fun car to drive! Question; when coming off boost there is a noise like air escaping. I assume this is a waste-gate valve (or whatever it is called) bleeding off excess pressure. The power drop at this point is rather abrupt however, and sends a mild but noticeable shudder through the drive train. Rear end is howling a bit so I am thinking pinion bearing and u-joints. How should a "perfect" SVO behave going from boost to backing out of throttle; as in steady 7-10+ lbs up the on ramp to easing out as traffic builds.

[Meotchh]

It should act like any other car when backing out of the throttle.

Does it have any issue building up boost?
Do you have any modifications such as a bypass valve or aftermarket boost controller?

The rear end howl could be axle bearings. U-joints typically will cause squealing/squeaking noise.

Are you going to the show at Griott's Garage on Sunday?

[Paulofolympia]

It builds boost. Stock boost controller. Some new plumbing to controller last year per SVOCOP recommendation. No squealing or squeaking; but a dull howling back there (at lower rpm's-easier to hear?) and a shudder/judder on post boost. Not quite like any other car. Yes I am going to the show at Griott's and would appreciate advice. Thanks.

[SchoolBoy]

Sounds like compressor surge doesn't Mike?

[Meotchh]

I guess you didn't make the show.
Did you check to make sure you have no vac leaks after all the work that was performed?