Back when I was a diesel tech at a dealer, I had a 08 6.4 that stalled after driving for a long time. I spent hours driving it with the IDS trying to verify the concern. After a while it died and I had to get a ride back to the dealer. It lost fuel pressure on the high side. Ended up changing the high pressure fuel pump and that fixed it up.
Don't know if this helps or not but it may give you something to think about.