Did you stop when the handle clicked or top it off? That would affect your mileage too, if you squeezed and extra 2-3 gallons in it. Some owners have put in 16 gallons before (and had I think 1150 miles on that tank). My fuel light came on the other night, it dropped to no bars for a few seconds then back to one, and I only put in 11.5 gallons. It clicked a couple tenths before that, but I rounded it to $27. I don't plan on topping it off, but mine doesn't like it anyway (will click very easily even adding just a little bit more). It seems like your guage is way off if you didn't top off. Yes, you are right, a ULEV (most states) has a 13.2, and an AT-PZEV (CA & NE U.S.) have an 11.9 gallon tank.

But if I assume you topped it off like a fellow GH member, than you put an extra 3 gallons in it. You would then have around 47 mpg. The computer on mine said 44.1, but by calculation I had 46.8 (2.7 mpg variation). Add that 2.7 to your computer calculation and you would have almost 47 mpg. I know this is all guesswork, and also not knowing your driving style. I know someone who was getting 34.x, changed thier style after a little coaching and jumped by 10+ mpg.

If you didn't top it off, and it concerns you, The car is under warranty, so take it in and have them adjust it. I would rather it say I have less than actual than that much more!!! I am really hoping for that reason that you filled it to the brim.

Take care and get back with us about the circumstances!