Colder weather will let you get away with a lower octane fuel
Octane has nothing to do with miliage but, with electronic retardation systems the EMS may run a richer, less fuel efficient mixture.

Ethanol will also give you lower mpg's as it contains less energy per gallon. However it improves Octane and allows for the cold air compression increase. Each engine map will operate differently Ford, Lexus, Camry etc but our little 3.2's ought to operate the same.

I'm surprised MDaniels gets lower milage in cold weather. The fuel should be denser as well as the air yet it should pack more power per gallon and per Cubic feet of air volume. Perhaps he is running rich to compensate.

I used to get 27 MPG highway. After my tunes I get 29.5.

Shell v power 93 unless I can't find it.
BP 92 seems to run fine and give me the same milage.

I run sans Ethanol whenever I can. It is simply immoral to burn food in our cars.


roadster with a stick