Supercharger Bypass check valve sticking?
 

So I was doing a few full throttle runs today and after one of the runs, when I got off the throttle the supercharger was making a rather loud moaning kind of sound. Shut the car down, Restarted, no noise. Another run produced the same result. I thought that maybe the bypass valve was getting stuck, but the vacuum actuator is good and the linkage moves freely. I then started thinking about the noise the car made when some idiot(me) put the idle valve on backwards. I'm pretty sure it's the same noise. My theory is that the Bypass check valve( the check valve between the hose from the intake to the idle valve Supercharger Bypass Check Valve (90-00) ) may be getting stuck shut. Anyone else have a similar problem?

Check to see if the bypass valve is torn. These can die after a while. Not often, but is considered part of SC maintenance.

Remove the SC belt, check nose pulley for play.

I would imagine that if there was play in the nose pulley, the issue would be constant, not intermittent.

I'm talking about the check valve that goes to the idle valve, not the bypass valve on the supercharger itself. That is functioning fine.

Sorry, I should lay off the beer when trying to help. If you really think the checkvalve is a problem, then take it out, reconnect the hoses and test. It's not an imperative item on your setup. It was actually a small upgrade for SC kits so boost wasn't leaking past the IAC. You may see a small drop from .5-1 psi with it off, if you do at all when in WOT.

Remove bypass value, run full boost at idle like a man.