Another Update : I increased the tire pressure to 70 psi. I use 87 Octane and filled up at the same pump friday night, drove 157 miles (mainly highway) round trip back to the same pump and filled her up = 9.333 gallons. 157 / 9.333 = 16.822 MPG. This is NOT taking into consideration that my odometer is off 1/2 tenth per "measured" mile. So for every 10 miles registered on the odometer, I have actually traveled 10.5 miles. So ACTUAL MILES would equal 157 x .05 = 7.85. 157 + 7.85 = 164.85 / 9.333 = 17.66 MPG HIGHWAY. Who believes air pressure doesnt make a difference???