The 2005 Mustang had tank filling issues that were initially dealt with early on in production with a redesign of the tank but I do remember hearing of complaints about the filler neck design from the first few years of the S197 not being on enough of an angle and it being installed at the factory at a suboptimal position that made things worse on some cars. I've read that readjusting it that little bit that you can will improve the gas filling.I experienced a similar issue last night, returning home from Baltimore. I experimented with different hose positions until it began to fill the tank. I hadn't had this problem in several years. think my issue is related to the pump.