Last time I drove my truck, I topped off just outside Milwaukee heading back to Chicago. The whole trip is mostly contruction zone, so speeds were around 55mph, sometimes up to 60.

I've also done a tiny bit of bopping around the 'burbs here-- I figured I'd show my typical 18.x mpg when I topped off.

The tank took only 4.9 Gal-- 120 miles on it.

This was a different station than I normally use, and the truck was parked on a slight uphill which might reduce tank capacity a hair.

Anyway, I thought 24mpg was pretty darn good for this big beast.

Smarty on #3 seems best all around for driveability and MPG with big injectors. I get better mileage on #3 than on #1.

Hmm.

 

I have an 01, and do a typical 18.x too. 24 is cool, but I would want to know why.

 

The problem with this "top off" is that a variance of .2 to .9 gallons tank capacity (based on the incline of the truck when being filled) can skew things a LOT when you only put in 5 gallons. When you you put 25 gallons or more, the variance is much less.

Still, I figured that even if it took 6 gallons (which is extreme in the variance), then it would be dead even 20mpg-- still great with all the city driving mixed in there.

Anyway, I'm more than pleased with the mpg my truck is currently getting.

It's consistently better than stock-- even with 150hp injectors!

 

Yeah that's pretty good. My all time best is 25 mpg from Barstow to Las Vegas. I think there's a slight overall decline in elevation though...