I've stalled out due to a faulty siphon pump. Check the cluster OBC tank level readings, the pump side (right IIRC) will be 0 and the left will show fuel, if the siphon pump fails.

I've also had a fuel pump die on me once. Truck wouldnt start leaving from home. Verified no fuel pressure in the rail by depressing schrader valve and verified fuel pump relay was working. Decided to try the pump first and it turned out to be it in my case.

EDIT: Also, I remember the broken siphon pump only caused a stall condition for me if you got below a certain fuel level, around half tank. Above that the truck ran fine in my case.

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04 X5 3.0i auto
03 X5 4.6is