Never bad fuel from any mayor fuel companies. However, Bio-diesel is a different animal. Traveling from St Louse thru Kansas, we fueled up, however we put in Bio-diesel, Coming into Dodge City you guessed it, fuel problems. Stopped at the Freightliner and had the filter changed out. Found out the BD used in that area is animal fat, and when it gets cold. Well, our power dropped from 65 mph to 45 mph. Think about this, if a mayor fuel farm was putting out bad fuel, wouldn't you see trucks on both sides of the highway?