I can say that my average of 18+ for highway driving from MI to TN in Sept, consisted of highway speeds around 75 from MI to TN, and in TN at 80 mph.
Almost the entire trip was set with the cruise on. From MI to KY is primarily flat, from Louisville KY, to Elizabeth Town KY, is hilly, from Elizabeth KY to TN border is primarily flat with a few rolling hills.
From the TN border Northern Nashville is flat with a long decline at Ridge Top. From Northern Nashville to Centerville, is hilly.
Trip home produced almost the same identical mileages.
This was on a new engine, not even broke in, temps were anywhere from the 60s to the 80s.

with 4k on my automatic I get 16 around town my commute is 25 miles and about half freeway and half city I average 18 and thats going 70 on the freeway. On a run back from a trip to pismo truck loaded and 40 psi in tires got 21.5 mpg cruise was set about 63 and openroad for 200 miles was very pleased . So if your not in a hurry and run your tires a little high on pressure you can get over 20 mpg with an automatic .

Wow my first tank of gas got about 12 - 13 mpg mixture of City / Highway driving. This time I filled up with 89 and well see how that does on the second tank. Hopefully gets better when the engine gets broken in.

First two tanks got 16.5 on 87.

I was tracking it for about 8 tanks.....12-15mpg city/14-16 highway...but I have a very heavy foot...mostly 75-85mph on the highway. I was a little dissapointed, but in the end I just said "scr** it!"...it's Got2B cause of my heavy foot! I've very much enjoyed the way it drives.

what grade fuel is recommended in the H3? I'm new and considering buying an H3 in the coming months..

Per the manual, regular. No problems running regular on my H3 for 6 months.

S.

thanks for clarifying... was expecting to hear that you needed to run like 89-91 octane for optimal performance....

Most accurate way to check mileage? Fill up, set 0 on trip, then drive, wait till empty and divide mileage by 23?

Is there a more accurate way?

not even close.

fill up, keep up with mileage, fill up again, divide the amount of fuel it took to fill back up into the total mileage on the previous tank and voila.

Do that on a couple of fill ups and you know what your average is.

BigDog

what do u do when u run out of gas?

RYD

filled up for the first time the other day got 16.8 city/highway. if you have the adv pak the highway miles is poted at 19 instead of 20 for base pkg

It you calculated your mileage correctly, I think you got the highest mileage anyone has gotten out of their first tank.

15 mpg Highway/city combined with the stock 265's, I'm looking to go to 285's let's see what happens.

1. first tank before all my mods = 16.8 mpg/city

2. after marker lights, sidesteps and splash guards = 14.7 mpg/city

3. SMA brushguard and fog lights = 14.2 mpg/city

4. 35's = 12.8 mpg/city after my first tank.

5. Gobi rack and offroad lights (next) = ??????

My mileage has crept down lately to about 14.7 mpg (from 15) running around Silicon Valley (city combined with fast freeway driving). I consider the mileage to be acceptable for this type of truck running on Chevron regular.

My H3 was purchased in July and now has 15K miles. Tires are stock 32".

S.

About 6.5K, and 15-16 MPG. Nothing to write home about. But then again, I do run it agressively around town...and why not...it's YELLOW!

You would have thought that the 5cyl engine would have provided more results. Especially given the available power. Dissapointed. I guess I'll have to upgrade to the Alpha, or the TD when it arrives...that'll show 'em!

15 all around, and I'm not easy on it.

Okay, I've got just over 800 miles on the H3 and just finished my first mileage check. Right now with mostly local and a few 10 mile jaunts on the interstate I'm showing 15.778 mpg.

My F-150 5.4 V8 that I traded was getting 13.8 mpg local.

6600 miles.
As low as 11 mpg around town for a daily 6 mile commute.
15 mpg doing 80 mph.
21 mpg doing around 55 mph.

Cruise control supposedly gets better gas mileage because a human foot keeps moving just a little and thus pumps unnecessary gas in.