hmmm my crx with b20 swap idles a bit weird too and simliar to your case. Maybe ill get an answer from this thread as well lol. I did clean my IACV and it still fluctuates at idle. And no, my throttle body doesnt have a FITV which i heard contribute to the idling problem as well.

However, I am running on a PR4 ECU which is obd1 since my car got converted from obd0 to ob1. As for your concern with emission related, it passes emission with flying color though.

Also since u said that your rpm didnt drop 100 when removing the plug from the IACV i think it means that u might need a new one as stated from that site.