Even with filters on the pumps, it's possible to get bad gas. When my zetec was chipped and running on premium, I tried walmart 93 once and it made the car run bad. That's the only time I've gotten bad gas.
98.5 SVT
91 Escort GT (almost sold)
96 ATX Zetec (i brake to watch you swerve)
FS: SVT rear sway bar
WTB: Very cheap beater
CEG Dragon Run - October 13-15