Ok, well this has been driving me absolutely nuts for the past few weeks. My idle's been surging between 1500 and 2500 rpms. I took off the FITV today and screwed the white plastic screw shut, hoping this would solve the prob. It didn't. I took off the IACV on the back on the IM and checked that, looked fine, screen wasn't clogged or anything. I have the idle screw on the TB all the way in and even when warmed up, it won't idle anything below 1500rpms.
Now here's the catch and maybe the answer to my probs... I spun a rod bearing in my b18c and replaced that with a JDM b16a. I bought the motor from a local shop and traded my p72 ecu for a chipped p28 to run the b16 with. So I plug the p28 into my car with the b18c still installed, because I had to move the car. The idle was surging with that motor. When I did the b16 swap, I used the GSR TB on the b16 IM because I didn't want to deal with swapping throttle cables and all that crap. So I'm having the same exact problem. I thought it might have been the FITV since that's attached to the GSR TB, but screwing it shut did nothing. I tried resetting the ECU, nothing.

The ECU itself has been socketed for Hondata however... and I'm thinking maybe this has an effect on my idle? I thought socketed meant easy removal of where the chip plugs in, but maybe I'm wrong. The guy who I got the ECU from re-programmed and re-chipped it right in front of me, so I don't think I was given a bad ECU. Any insight would be greatly appreciated... this seriously sucks.