mine avegeres around 17 but ive only got 6k on it but idleing kills the milage on mine faster than anything especialy if you go by the overhead if you go by it taco bell cost me 3miles to the gallon ever time i stop there

 

just filled up mine... 450 miles.. 16.3
only thing diff.. 12 oz PS...cenex fuel
and did i mention she burns the tires pretty easy in the rain
tow/haul 80% od/off 20% 4 min startup warm and 1-2 min cooldown
most of my miles are at 50-55 mph one trip going 65mph 100 miles

this next tank safeway fuel no PS 400lbs of sand well see

 

My suggestion - get a better drop-in filter. I changed mine to a NAPA Gold 42846 Air Filter after 3K miles. It was the best mod I have done for the least price ($13). Immediately after installing the filter, my mileage went up and the truck definitely had more power (and the turbo spooled much faster)

$13 is a small price to pay for that kind of difference. Get them at www.fleetfilter.com.

 

The first thing I did when I left the dealership with my new truck is stop at a gas station and pump up the tires. The fronts were at 52 psi and the rears at 50 psi. I put 68 in the fronts and 52 in the rears. Tire pressure has always played a big roll in mileage on by big trucks. Like 1-2 mpg.

My last fill up was from 1/2 a tank on the nose (trying to figure out how much fuel I have left from different levels on the guage) I had 351 miles on it and it took 18.3 gallons. That is 19.18 mpg hand calculated. I fill up my tank until the fuel is at the filler neck where the return hole is. So, this is very accurate. This is with 80% hwy and 20% city driving. Hwy speeds averaging about 65 with a little 60 mph up to 80 mph thrown in.

This is not too bad considering I just turned 1000 miles on this last tank.(1063 to be exact). I do use 8-12 oz. of Power Service every fill-up. I don't know if it helps but I like my fuel pump and cp3!

 

I guess I shouldn't complain. I'm getting 16.5 rural driving, 15 highway (70mph, 2300rpm) This is pretty much the same mileage I've gotten from the get go. 15 k miles, 2k of which were dragging a 10k Fifth wheel up and down the smokies. Put the trailer on and go 63 (2k rpm) and I can possibly squeek 11 mpg on flat land. Pulling at 70 and I plummet down to a whopping 9.5 mpg.

I'm hoping that as I get more miles, I can break that 17 barrier.

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