Well, Frome what I have learned from all these helpfull people is "its prolly not bad, its just not like everyone elses".
It seems that many people are having new issues with their warm-up valves (or their like me in Florida and are just learning they have one) but each story seems to have slightly different characteristics.
Mine was a lot like yours, but bringing the idle up in a parking lot prolly isnt a good test since there is no load on the motor the rpm will be greatly effected when the valve opens and closes as your noticing. Mine stayed this way for my entire 45 min drive to work. Then ran 100% normal later int he day when the air temps got above 40. Once your out driving is the real test. Some people are like me and it only opend at low throttle and will close as soon as I accelerate harder or let off the pedal completely, others say their stays open Full-Time untill the truck is at its desired temp. But, the thing they all seem to have in common is, the truck acceleration will suffer as boost will not produce with the valve open, and two, both of these are instances where the truck operating normaly and not a reliability issue.
But yes, it sure does freak us all out when something changes on our trucks, so I understand your alarm.
As for an update on my situation, we had our coldes night in Jacksonville last night. But, all was well with the truck this morning. It did not require any repeated cycling og the ignition and it fired up as soon as I hit the key and ran smooth and quite.
Cause I had a freaking Block heater for the last 3 years and didn't know it!
I know, what a sad Ford owner. I never realized that plug above the oil filter was a heating element, always thought it was just a heavy duty temp/press sensore. It doest help that the previous owner seems to have purchased and extremely short aftermarket cord for it and tucked that into a nearby frame slot. When I decided to trace the line to see if it made its way up to the front of the truck, I gave it a tug and would you beleiv it there was a standard male plug. So I grabbed an extension cord, plugged it in, saw a tiny spark as I plugged it in that confirmed it was still working after all these years.
I got in this morning and saw that the "Wait to Start" went off much faster than normal even on a warm day, hit the key, fired right up, and I couldn't beleive it when I had warm air blowing as soon as I hit the control.