This is the exact reason why I highly recommend getting a set of these aero force gauges to monitor your IAT2s. I hopped in my car tonight to take it for a drive and my IAT2's were staying up around 140 degrees. Normally they stay between 80-100 depending on the temperature outside.
What happens is the inter cooler fluid some how air locks itself, and this is what happens. All you have to do is take a vacuum and suck the fluid through to get the air pocket out. My car was sitting for the last couple weeks and out of the blue does this. I didn't disconnect any of the coolant hoses either. The gauges are just the best way to tell you if your inter cooler pump is flowing properly.
I can't believe ford let the 03/04 terminators leave the factory without some kind of gauge to monitor IAT2's. That along with oil pressure and wide band are the top 3 most critical things to watch driving down the road
This has happened to me a couple of times over the years. Not a big deal as long as you get the air pocket sucked out and baby it while the system is air locked.