[mwebb]

you should try different brands of fuel
try to stick with fuels listed here
Top Tier Gasoline
you will find a significant difference between fuel your car likes and fuel it does not like , the car will tell you IF you keep detailed fuel mileage records.

bring your tire pressure up closer to 40 psi cold after verifying your max pressure is over 40psi

walk around the car after you arrive and touch the back of your hand to all 4 wheels near the lug nuts
approach the wheel slowly so you do not get a new tattoo ....if one is very hot ....
none of the wheels should be warmer than about the hot water in a water pipe .
front wheels will be warmer than rear but
if any wheel feels significantly hotter than the others .
find out why , could be a dragging brake or wheel bearing, which will frak up your mileage in a big way