My 91 is at around 850 -950, that seems a little high to me seeing that it is pretty much stock except for some different mufflers. What is the proper rpm idle range and what can I do to get it there? Thanks.

Is it Automatic or Manual? That makes a difference believe it or not.:thumbsup:

Stock is around 500.
Your IAC valve may be dirty and not working properly , the throttle may be sticking open or you could have a vac leak.
Need to clean and reset IAC first.

http://www.corvetteactioncenter.com/kb/questions/276/1985+-+1991%3A+Technical+Article%3A+How+to+Adjust+your+E arly+C4+TPS+and+Idle+Speed