I went out and started my truck today, temperature out was about -12 C. I started it and it went up on high idle after about a minute, didn't go into 3 cyl...and after about 3-4 minutes of ruunning, it kicked itself out and went back to a normal idle. Temp gauge was showing 120 on my attitude monitor if I remember correctly. I even tried the high idle fooler, wouldn't go back into high idle. Shut the truck off and restarted it and still no high idle...flicked the fooler on agian in finally in about 3-4 after doing so, it reved back up to 1200 rpm. Surprised me that the high idle would stop when the engine was still cold, I've had warmer days that it worked flawlessly

That's odd... ECT (Engine Coolant Temperature) is what is used to cancel the high idle unless something else cancelled it like brake pedal, throttle, etc...As long as the Coolant temp is below 140*F it should resume the last mode of operation.

I thought it odd too! I had it going about two weeks ago, high idle worked perfect and stayed on it until I kicked it off about 10 minutes after starting it.