While a little unrelated, I have noticed some consistent variation in gas brands. I've filled up using Exxon/Mobil gas and averaged 57mpg and alternated it with Shell gas consistently and gotten 61-62mpg. Both 87 octane. Other brands like Chevron and Arco give me 58-60.
What may be a factor though is the refinary from which the gas came. I've tried to use different shell locations and gotten similar results but I have yet to use different Exxon/Mobil locations.
Also changes in driving style like slowing down have given me higher tanks. Right now I've been averaging a little less than 65MPH and pulling just under 70MPG -- on Shell gas. Usually I do 70-75MPH and get 60-65MPG.
What may be a factor though is the refinary from which the gas came. I've tried to use different shell locations and gotten similar results but I have yet to use different Exxon/Mobil locations.
Also changes in driving style like slowing down have given me higher tanks. Right now I've been averaging a little less than 65MPH and pulling just under 70MPG -- on Shell gas. Usually I do 70-75MPH and get 60-65MPG.