I have got a 96 7.3 with a rebuilt motor with about 25k on it. Modded High Pressure Oil pump, and a new PCM, and a brand new CPS from ford. Truck has been dying randomly going down the road. Doesn't do it when you first start it up, starts doing it about 15 minutes after driving once its fully at operating temperature. Now all of a sudden, I went to start the truck, and immediately after I turned the key it began revving out of control. I immediately shut it back off, disconnected the batteries, and then reconnected and tried once more to start and it did the same thing.

 

Try disconnecting the throttle position sensor