Yeah the only way to get meaningful mpg comparisons is to use the same pump every time and fill up in similar weather conditions - getting the last galleon (4.5 L) in my 306 takes a lot of patience.
When I used to do a lot of regular long distance drives 500 miles+ I used to go to a nearby (cheap) esso station with a sloped forecourt and park with the filler cap facing up the slope (ie the high point) - it was much easier to get the last gallon in that way and I knew for sure that the tank was brim full.
I have never noticed any significant difference with mpg between brands - I use branded fuel because it is probably purer and possibly better quality control.
Long distance driving also helps mpg - short journeys will ruin overall mpg.
As others have posted - warm weather will give better fuel economy - but filling up when ambient temperature is low will get more fuel in your car as Bash posted .
When I used to do a lot of regular long distance drives 500 miles+ I used to go to a nearby (cheap) esso station with a sloped forecourt and park with the filler cap facing up the slope (ie the high point) - it was much easier to get the last gallon in that way and I knew for sure that the tank was brim full.
I have never noticed any significant difference with mpg between brands - I use branded fuel because it is probably purer and possibly better quality control.
Long distance driving also helps mpg - short journeys will ruin overall mpg.
As others have posted - warm weather will give better fuel economy - but filling up when ambient temperature is low will get more fuel in your car as Bash posted .
Quote:Temperature of the fuel itself. Expands when hot meaning less fuel for your money.