Join Date: Jun 2005
Location: Central Midwest (KS, MO)
Re: 20 mpg How do you do it?
i can chime in also for an 04 DC 4x4. it has about 21,000 miles. during the summer with stock tires it gets a steady 16.8 in mixed driving city/hiway. i actually get a little better around town at under 50 mph. on the interstate only, the wind resistance seems to keep it from getting better.
i have basic mods: hard tonneau cover, lsd, hellwig, etc. didn't seem to change mileage much.
biggest change was moving to winter tires. dropped it down to 14.5 - 15 on average including 5% change in tire diameter.
from reading lots of posts about this topic, i think the biggest difference in mileage is probably due to having 4x4 vs. 2x4. most of the folks getting over 18 have the 2x4 AC or similar. most getting under 16 have the 4x4 DC or similar or carry a lot of weight. i think the 4x4 rigging adds about 400 lbs to the weight of the 2x4. i have a buddy here in town with an 03 AC 2x4 and he gets 20 or a little better on the hiway. with my 4x4 i've never seen better than 17.5 mpg.
odd thing is even running around on back roads at slow speeds with occasional 4x4 use doesn't seem to knock it down much. still get about the same. if i punch it a little, though, that changes everything!
from other posts - to get the best mileage possible, try to keep it under 2,000 rpms, don't carry a lot of extra gear/tools you don't need, keep the drivetrain lubed and clean oil in crank, diffs, etc, and keep tires aired up. that's about all you can do with a truck this size!