So I’m trying to fix it up to make it a reliable daily driver and it is currently idling at like 200rpm and I think it’s because someone micky moused the swap (it has a f23a in it) the intake manifold has a iac valve in it which ment it was for a manual trans but it’s an auto so it should be on the throttle body and instead it just has a second iac valve just resting on the valve cover.

 

My 90-91's have an Electronic Air Control Valve mounted on the throttle body. I'm thinking the Engine Control Unit controls it to adjust the idle speed. The valve can develop some carbon deposits which can make the idle erratic or surge. Also it's important to be sure there is not an air bubble trapped in it's coolant lines. There is an idle adjusting screw but I've never messed with it.
Hope this helps.