7.3 Diesel van will stall the engine when driving. Dash lights will flicker first before stalling. After pulling over for a minute it will start. Sometimes I can drive for a mile before a stall happens, sometimes for 100 or more miles. I have cleaned all battery cables and posts. CAM Position Sensor was replaced by Ford 1 year ago.
All cables have at least two ends. I suggest cleaning both ends of the battery ground wire. You also should check the other end of the positive battery cable. Make sure it is clean and tight. Careful to avoid a short.
You also could have a bad battery cable.
What year make and model is your van?
Frankly I would look at the fuel pump. Just a hunch.