I have the same problem as described by Dwagenseller with my my 2000, 4.4i.
What I can add to the symptoms is that the problem appears only after 30 to 40 Km at the motorway (90mph) and not while driven same distance on secondary road.
When the problem appears shutting off the engine for 10 seconds will fix it. Cold air is flowing again like before, but it only helps for again 30 Km. This would point into something electrical, since I do a reset while shutting off.
It also helps to shut down the AC and press the button for defog the front window. After 1 or 2 minutes of warm air through the system I turn on the AC again and problem is fixed for a short while. This fix points into a freezing problem I think.
Hope this helps in diagnose the problem?
Besides I notice that when parking the car there is quit a lot of condens-water dripping underneath. Also after a short drive and after an average drive on secondary roads. Could this mean that the temp of the evaporator is not managed well?
Outside temperatures are 70F to 90F.