I just filled up at Costco today. My gas light came on at around 362 miles. Normally if I stop for gas within a mile or so of the light coming on, it takes between 9.2 and 9.3 gallons to fill to first click, where I stop. Today, at 374.2 miles (10.2 miles after the light came on), it took 9.558 gallons to fill. I get about the same mileage with Costco gas as I do with any other.