Filled up right as I crossed the border into Texas (Anthony) and then drove through El Paso heading east. About 5 miles later, the speed limit jumps to 80 mph and the mileage still showed 30.1 mpg 3 hours later when we stopped for gas. Two people in the car, trunk filled with detailing stuff, back seat filled with luggage. Actual mpg was 26.4, btw for that tankful.