Regarding mpg issues, there are other factors that affect my mpg.  One is
that when I'm at higher elevations during the summer, I get between 20-22
mpg, and when I'm in the flatlands during winter I get 16-19 mpg.  I assume
it's an issue of available oxygen.  Out here on the plains, the winds can be
devastating and my mileage goes way down battling the frequent headwinds.

Another interesting thing I have noticed is that when I try to compare my
speedometer to the speed on my GPS, I don't always get the same readings.
Sometimes when the speedometer reads "60", the GPS will say "63", other
times "65".  I have 15" wheels.  It's difficult to say what my exact mileage
or mpg is, but I don't think it matters much what actual numbers you get -
as someone said, only in comparison to your own vehicle.  So if my own
observations tell me I'm losing mpg in similar circumstances, then I start
checking to see what's up.

Maggie
'85 Subaru-Westy "Anne Bonney"