My car is having mood swings - Idle switching between normal and 4000+ RPM
 

I have been having a strange issue with my idle for the past few months, and I finally managed to get a couple data logs that might show it, but I can't find anything. Can somebody please take a look and help me? I am pulling my hair out!

I can tune the idle (open loop) to be nice and stable, and it will work fine for a few days, weeks, or even months. Then at random it will suddenly start idling very high. Like 4000+ rpm. It will do this again for days, weeks, or months. If it stays this way I can decrease the IAC duty cycle and again get a nice stable idle. Then at random it will switch back and the car will stall every time I put in the clutch until I go back.
So I've ended up with two tunes that both idle well at their respective "mood" or something. But I cannot figure out what is causing the two different moods!

I have checked every setting I can think of, looked for vacuum leaks, unplugged and reconnected any solenoid I can see on the intake manifold (I'll admit I don't know what most of them do). Nothing seems to make any difference.

I have attached the .msq that I have tuned with the higher IAC duty cycle, and a data log of each condition. Unfortunately I have not been able to catch a log of when it actually changes moods.