> I'm with Scott, measure out a quart and run it 'till it's gone and
> watch the
> clock.  It would be interesting to compare the calculted with the
> real
> world.

... or ... you could do what i did:
install a trip computer that measures the amount of fuel used by
counting the clicks of one of the fuel injectors. after calibration,
it was very accurate ... at least to 1/10th of a gallon.

and yes,i tested it at various rpm settings on the highway, and
measured the fuel consumption by time. and yes, i also measured the
fuel consumption at idle sitting in my driveway. :)

for a 1986 vanagon gl, 4-speed, with about 40,000 miles on it at the
time,
it measured ...

<drum roll>

0.6 gallons per hour.

and i'd say that was accurate (based on my experience with the trip
computer) to +/-0.1 gallon.

unca joel