Hey guys, 2 things...

Previous owner told me he gutted the catalytic converter. I'm curious as to know if this would cause my idle RPM to be slightly higher than it should be? I'm always around 1-1200rpms... Not sure where to look regarding this.

Second thing.... I'd like to "remove" the AC pump belt so I can get some of my engine power back and increase MPG... Would I be able to leave the pump in place but get a belt for a non-AC engine? I'm thinking of using the pump in the future for an on-board compressor if it's at all possible. Thanks!

 

High idle, especially on a Renix is most likely a dirty IAC or vacuum leaks.
The IAC (idle air control) is the silver thingy bolted to the front of the throttle body. Pull and clean.
Next check all the vacuum lines for cracks or being loose. Then spray starting fluid around the intake manifold where it mates to the head with the engine running. If the engine idle changes briefly, you have a leak. Try tightening the intake bolts/nuts.

A/C belt is non-issue. The pully free-wheels until the A/C is turned on.