I have an '03 GMC Savana cargo van, 4.3L V6, 3.43
axle, 1,900 miles on the odometer, with a 1 1/4
ton cargo capacity.
Just drove from Los Angeles to Monterey California
and back (round trip about 700 miles), and
averaged 20.1 MPG at 70-80 MPH on the 101. No
squeaks, no rattles, no wind noise.
There are many steep grades, congested traffic
getting through LA, Santa Barbara, etc. Four wheel
ABS disc brakes, rack and pinion steering, haul a
ton and 1/4 and get better than 20 MPG.
GM has done a great job on these '03 vans.