There is no way anyone is getting a 25mpg average per tank. That is impossible. It always cracks me up how people seem to stretch thier fuel mileage, but never the opposite direction. As I said, when I see someone post up some real numbers, I will believe it. I am not talking about just dividing the number of miles drive by the gallons it takes you to fill up one time. I want to see some history. Until then, keep dreaming.
Here's the data I currently have entered in at
Fuel Economy. I need to update it for 2012 but you'll get a good picture of what I'm seeing. Under the "Notes" is the number of gallons my ScanGaugeII "thought" I had burned when I filled up. Please excuse the formatting errors as I exported it to Excel, deleted some fields that didn't add to the discussion and then copied and pasted directly. Notice my tank on 5/01/2011 at 23.2 MPG. This was the one that contained the Yosemite trip mentioned earlier. The 8/07/2011 tank at 22.5 MPG contained my trip to Mammoth (actually Devil's Postpile beyond Mammoth) as mentioned earlier as well. A number of these tanks would read higher if it weren't for the fact that most of them get a good chunk of city driving at the end of the tank because I almost always fill at Costco in the major cities on the way back to our town since fuel is 20-30cents cheaper than at home. I don't know that there's a "highway only" tank there.
Date Odometer Gallons MPG Notes
11/14/2010 35474 18.723 First Fill
11/22/2010 35893 19.458 21.533560
11/27/2010 36251 17.586 20.357101 17.4i
12/05/2010 36580 14.961 21.990507 15.2i
12/18/2010 36998 19.120 21.861923 19.3i
12/23/2010 37430 19.943 21.661736 20.1i
12/31/2010 37851 19.584 21.497140 20.1i
01/19/2011 38227 21.307 17.646784 21.3i
01/29/2011 38478 14.026 17.895338 14.2i
02/19/2011 38841 20.254 17.922386 20.4i
02/21/2011 39052 09.510 22.187170 9.7i
03/12/2011 39323 15.331 17.676603 15.2i
03/14/2011 39666 14.907 23.009325 15.6i
04/02/2011 40020 20.148 17.569980 20.2i
04/16/2011 40477 23.014 19.857477 22.9i
04/25/2011 40819 16.204 21.105900 16.6i
04/26/2011 41229 19.579 20.940804 20.1i
05/01/2011 41734 21.767 23.200256 22.1i
05/29/2011 42118 21.767 17.641384 21.7i
06/12/2011 42391 13.769 19.827148 14.1i
07/02/2011 42835 22.260 19.946090 22.7i 1.9reservew/SB91oct
07/15/2011 43169 17.340 19.261822 17.3i
07/31/2011 43574 21.018 19.269197 21.1i
08/07/2011 43978 17.982 22.466911 18.2i
08/17/2011 44234 13.249 19.322214 13.2i
09/04/2011 44784 26.284 20.925278 26.4i
09/18/2011 45072 14.799 19.460775 14.9i
11/08/2011 45393 19.530 16.436250 19.5i
12/10/2011 45712 19.880 16.046278 19.8i
12/28/2011 46114 20.700 19.420290 20.7i
Note: I just noticed that my 5/1/11 and 5/29/11 fillups came out to the exact same amount of fuel to the 1/1000th of a gallon. I suspect I transcribed in error so I'll look back in my fuel log in the vehicle and see if they match.