First off, I wouldn't suspect the aux air valve as yours is obviously basically working and if sticky it usually only drops intermittently, and won't rise intermittently. BTW Make sure you tap on it a few times before setting warm idle to make sure it's shut all the way (there will normally be a small crescent of light getting through even when warm).

Now if it was a rough idle I'd be more interested in vacuum leaks, a leaking cold start injector and leaking injectors seals, but that doesn't appear to be your symptom -you say your idle is jumping around, especially when warm.

As I recall, the B20F K-Jet system uses a dual coil fuel pump relay, one coil is used for the fuel pump and the other coil for the control pressure regulator. If that section of the relay starts to fail (causing intermittent control of the CPR) then you can have symptoms such as you describe and they would be most noticeable when the engine is warm. You could try cleaning up the internal contacts and re-seating the relay. If it's not then a failed CPR would seem a probably cause as you suspect. I'm sure there are other possibilities.
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Dave -not to be confused with a real expert