I would check the fuel pressure.
If you were at about 1/3 of a tank of gas, I'd suggest looking up Andrew Wynn's post on the 99 cent Oring in the fuel pump siphon. He lists a procedure to check the status of the left and right side fuel levels by opening up the diagnostics on the gauge cluster.
This happened to me and it was the O ring. Fairly easy repair but really annoying if you are at a rest stop 30 miles from home with two small grandkids heading for the beach. The short term solution to that situation is to always keep over half a tank of gas until you change the o ring.

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2001 x5 3.0 (sold with broken motor), 1990 e30 M3, 1991 318is, 2002 325i, 2008 335i Dinan stage 3 6 speed,