As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FUEL TANK SELECTOR VALVE, WHEN THE VALVE WAS ROTATED, IT WAS STIFF TO MOVE AND COULD NOT FEEL THE DETENT AT EACH POSITION. A TEARDOWN OF THE VALVE SHOWED THAT THE VALVE WAS VERY DIRTY INSIDE AND THE DETENT RING WAS WORN. DEFECT LED TO IMPROPER FUEL SELECTION, GREATLY REDUCING FUEL FLOW TO ENGINE CAUSING ENGINE STOPPAGE.