when I shift, the throttle stays open.
any suggestions?

 

Take your foot off the gas?

If the RPMs climb up when you clutch in for a gear change make sure your throttle cable isn't bound up. Make sure your return spring on the throttle body is still working. Go clean your throttle body and IACV really good with throttle body cleaner (autozone/oreilly), and put white lithium grease on the springs on the outside to help keep things lubed.