when you cleaned the throttle body, did you notice if the butterfly was closed?....my photo shows a throttle body off the car and you only see the tiny gap because I shone a flashlight behind for the photo.
I can imagine if the butterfly is not almost closed it would cause all sorts of idling problems.
The throttle stop is factory set and capped off, but some PO mess with them when there is a problem elsewhere, like a bad ICV or bad TPS etc.
check the throttle stop is just in contact with the throttle mechanism and not so far screwed in it is keeping the butterfly open.
As I recall the butterfly looked 'closed'.
This was messed with, however, I doubt that's the issue because I backed it off completely
and there's no change. I set it to touch + a tiny bit.
Plus, if I keep it running for a few minutes until it warms up,
it will idle with the ICV connected. It hunts a bit, but it won't stall.
It only stalls with the ICV connected when it's cold.
If that was the problem it would persist when it was warm, no?
To back up to the beginning:
When I first got it in summer, when the ambient temp was high, it idled with the ICV connected.
It was oscillating between about 900-1000, but it didn't stall.
It started stalling as it got cooler outside.
If I warm it first, either by keeping up the RPM's or disconnecting the ICV, it idles like before - some hunting but it doesn't stall.
When I first start it, it smells rich. About the time it warms up a bit and stops smelling, it will idle with the ICV connected.
So what controls the idle if the ICV is disconnected? With the ICV disconnected the idle won't drop below 1k even with the throttle stop backed up all the way.