Download ISSUE Some 2005-2008 F-Super Duty 250/350 vehicles equipped with a 5.4L 3V or 6.8L 3V engine may experience premature automatic shut off of the fuel fill nozzle, or repeated fuel shut off at the fuel station delivery nozzle with malfunction indicator lamp (MIL) on with diagnostic trouble code (DTC) P0191. Vehicles operated in muddy or dusty environments can encounter a dirt clogged carbon canister system. More specifically, the carbon canister’s vent, fresh air box, and filters become clogged with dirt from operating in such environments. SERVICE PROCEDURE Inspect the vehicle canister system and if it found to be dirt clogged then continue with this TSB. NOTE IF THE VEHICLE’S CANISTER SYSTEM IS NOT DIRT CLOGGED, THEN PROCEED WITH NORMAL DIAGNOSTICS AND DO NOT CONTINUE WITH THIS TSB. Vehicles with Pickup Boxes: 1. Replace the carbon canister assembly with a canister built after 10/1/2006.