Stewart's Gas?

[ceres]

Anyone in the NY area ever get gas at Stewart's (they have locations only in NY and VT). I have twice filled my Yaris there and both times gotten horrible milleage. I know other threads people have been saying how they don't get good mileage. It could just be the gas they use if they regularly fill at the same place. I seriously get around 100 miles less for the tank. On a 11.1 gal tank that's a reduction of just over 9 mpg. I went to the same Stewart's and it's been just over a month since the first time I tried it. I'm wondering if anyone else has noticed this or maybe it's just that Stewart's. I may try another one to see if it gives me the same mileage. That just seems like a ridiculous difference from when I go to Sunoco or Hess (I avoid Mobil at all costs since they usually have more expensive gas).