RE: Milagae with an automatic
I routinely get 17-18 and as high as 20 (under ideal conditions) on the
highway with my '90 Westy loaded out to over 5,000 pounds.  Having the
injectors rebuilt seemed to help a little but not enough to claim and
advantage because other things were done at the same time.  This is running
185R14 Agilis tires.  I've done several trips with an '87 Westy, automatic,
running 16" wheels and tires (lower profile tire so almost stock
circumference) and even though he is about 350 pounds lighter than my rig
when we fill up together along the way we are usually within a tenth or two
tenth of a gallon on consumption, worst difference we ever saw was 1/2
gallon.  BTW, my mpg figures are based on odometer readings and those are
almost exactly 2% low based on measured rive mile speo checks along the
highway.