Are you guys taking into account your new tires with these numbers? I gps'd mine and I was 1 mile an hour high at 70 with 275/70. So that means that people with factory tires could be way high on speed and mileage.

 

they could be switching over to winter gas already or adding diff addditives to the gas in your area, maybe it's not something that you are doing wrong

 

I think it was my air pressure. 29-30 PSI? I guess the sudden cold front affected it. Anywho, its back up to 35 on all four corners...we'll see what happens next tank!

 

That's what happened to me. My air pressure was down to 27 PSI after my car sat outside of my dorm in the cold for about 3 weeks without being driven. Gas mileage went down a little, so I checked my pressure and went back up to 35 psi. MPG went back up to 20.5 on the highway.