Yea, IAC's can take a hit in cold weather with the 5fours. That's if you run the engine in short drive cycles or just idle it for awhile and shut it down. This promotes sludging under the cam covers and you can't get away from it, other than driving longer distances so the engines has time to rid itself of bi-product,- moisture. This isn't a problem unless you do it continuously. The bad in all that is the PCV valve, system and IAC can freeze up. The IAC on the 5fours is at the back of the TB elbow. The PCV line is right next to it, so yea, the IAC can be attacked thru that line. If you notice, the 99+ PCV lines have an insulator wrapped around the line. That's due to the 97/98 problem in the past. In 2000, they went so far as to equip these engines with a cold climate system, where a coolant line wraps around the PCV valve itself. Both additions where to combat cold climate problems. The 4six IAC however, is at the front drivers side of the TB elbow which doesn't end up compromised from cold weather.