Any suggetsions??

[Koshin]

What's up guys (a few girls), got an s13 with a redtop swap and am wondering whats up with my idle?? When the car idles, sometimes the idle is 800-900 rpm, sometimes its up around 1100-1200 rpm. ?? I was going to at least clean the IACV before I bought a new one, but I cannot get the screw to budge. I searched and found the thread on cleaning the IACV with carb cleaner. The "plastic" screw that everyone refers to, well mine is metal and I cannot get it to budge. What else might cause a speratic idle like this. The car runs really well, really well actually. Anything else I should check for, and whats up with my IACV screw?? Thanks