Ok, here's the deal...

my 91 CRX Si has a quirky idle when it's warm. I've already replaced the coolant temp sensor, cuz I was told that that sensor can cause the idle to be erratic if it's faulty. But, the idle is still a little screwy. For example, when I come to a stop light, sometimes the engine goes waaaaaaaaaay down almost zero RPM, just barely turns over, and after 2 or 3 seconds it comes back up to normal. Other times, it'll go waaaaaaaay down to almost zero, and actually stall out.

This doesn't happen every time I stop, but I'd say maybe 1/3 of the tiem it does this. The stalling thing is more rare, maybe 1/20 times it'll actually die out.

I've been told by a couple mechanics that, if the Idle Air Control Valve goes bad, that symptom can happen. Also, I was told that Honda IACV's don't respond well to cleaning, they just have to be replaced once they get old and die. Anyone ever had to replace this? The engine has 182k on it, its a stock D16A6.

I also need to scrape all the black crap off of my throttlebody butterfly, it's pretty bad. All the so-called cleaners don't work worth a sh11t. So, I'm just gona get in there with a toothbrush and some compressed air and try to get it clean. Any ideas? Thanks