I actually been calculating my gas mileage every time,
I tried premium twice and it actually gave me the exact same MPG's the first time and .5 less the second - plus it made my truck run way too rich. Medium grade is the best IMO.
Needless to say I yet have to do the O2, coolent sensors ( still too cold here, have icicles all over my frame still )
If you replace the Oxegen sensors a good tip is to heat the engine to 120 degrees and don't forget to put a little anti seaz on the new ones.
For the coolent sensor don't put Anti seaz any lower than the 2nd thread. Otherwise you could mess up the sensor area.
Hope that helps - BTW your gas mileage is good
![Smile :)](./images/smilies/icon_smile.gif)
this winter I got an average 11 , (city only)
Have a great day