I just bought my car about a week ago, its a 96 GSR with JRSC running 11psi. It uses the CRV pulley?

Anyhow everything has been great up till yesterday when I'm driving along and I get into it and all of a sudden I get to about 6k and the car pulls back drastically, felt like some major detonation and I looked at my boost gauge to see 15psi.

So I'm at a loss here because I do not see how its possible for a supercharger to all of a sudden start making more boost then its supposed to. My one friend say last time he saw that was due to the engine being blown so we did a compression check and everything came back fine.

What happens is you'll be driving around like say I take off in first, shift into 2nd and floor it it goes up to 11lbs almost instantly and then it sounds like some scuffing kind of noise and the boost gauge jumps to 15lbs and then the car pulls back and the boost gauge drops again to 11lbs.

I need help, anyone have any idea whats wrong and how I can get the boost back to a steady 11lbs?