Hello, well first off the ac contol's are not vacume operated on these truck's, they are full electric so that's not the problem with those. I assume that you reconnected the single wire, and then a couple hour's later it started again. The first thing I would check is the IAC valve or idle air control valve, it control's the idle speed of the engine, these do go bad from time to time. It is the cylindrical item that threads in to the passenger side rear of the throttle body, it has a pintle shaft that can get worn and they also sometime's get stuck. If that's not it I would personally hook up a live data code scanner and view the data, and see what's going on. You could also look over all of the electrical connection's and see if any of them are dirty or corroded.
