Dang...I'm too late, but I'm glad you found it.
My 2000 F-150 suffered the same problem. I cleaned the IACV and throttle body, no more problems.
There are a lot of good websites out there for the F-150, must be as many for your Exploder. (no that's not a typo

)
A local dealer wanted 80 bucks to look at it and around 400 to repair if replacement of the IACV was necessary. Take your VIN # when you go see the parts guy at the dealer, that will help him select the right part for your vehicle.
The same dealer tried to tell me it was going to cost me 730 bucks for a front rotor! I bought 2 rotors for 112 each from Stillen Motorsports, and unlike the dealer models, these are crossdrilled.
Good post man.