Eclipse gst idle problem?

my car has the stock turbo its a 97 the other day i was driving and was going to take a car i steped on the gas and my turbo was spooling all the way i looked at my rpms when i shifted and when i pushed the clutch in my rpms jumped up about 500 rpms....and ideas what could b causing this.....it does it all the time now if i make my turbo spool up- all the way and shift...thanx for the help