i wanted to see how everyone is doing on mileage. Hyundai says the tank is 14.5 gallons but I have put in 16 gallons when the car is totally out. I usually average 405 miles on a tank when I driver 70 mph or under freeway driving. Thats on 89 gas. Wednesday I filled up with 91 octane and as of this moring I have 460 miles and it is still running. I bought a gas can and put a gallon in to see how far this will go. This is my record, Im sure I can get another 15 miles before I'm out.Thanx SuperGLS for doin' this.