The GF was towing a trailer and the weight of the trailer was sufficient enough to allow air to enter the fuel line and starve the engine. I towed the same trailer with her truck before and didn't experience any problems, only this time she allowed the low fuel warning light to come on and thought she could make it to town. Thanks to everyone who may have read my post and not yet replied.
This "Hotrodders Bulletin Board" website is the "Best". Thanks again to everyone.