JCLeary

I don't know why you're complaining...

I have an '07 5.9 that's all stock. It has 3.73 gears.

I've filled the tank 7 times since I bought it. I have gotten between 12.6 and 16.1 MPG per tank, all hand-calculated. Average MPG of all tanks is 13.9. Granted, some of this mileage is towing, and a lot of it is in the city. This mileage is not so different from my '03 with a 6-speed, but it had 35" tires.

I think it's pretty remarkable that the new 6.7 gets the mileage it does, along with all the emissions junk and extra power. If I knew my new 5.9 would not be much better, I think I would have purchased a 6.7 with an auto and 4.10's and leave the motor stock for the life of the truck...

eodshawn

I have 37s on mine and I get around 16 hwy and 12 in town

Hopper

[QUOTE=toyking;1780473]Then again it does depend on what kind of Tonneau cover you put on. I personally put a Pace Edwards jack rabbit I believe it's called. Its the Hard cover that rolls up toward the front of the bed. Yes I did loose about a foot of bed space... but I'm mostly empty so I'd rather have the cover.
QUOTE]

I should designate that in my sig. I have a tard top that opens like the hood. Don't know who made it, but it's a heavy SOB. Prolly 110 lbs with both of the hydraulic pistons blown. Need to use all those glutes to get that thing off and on by myself.

tmcblane

I have been getting 12.6-13.5 driving and 7-9 towing max load. 4x4, dually w/4:10's stock tires. Got the G30 recall done today and so far it looks as if mileage may improve.

G-NOTE

Wow, I am NOT complaining...

Just comparing figures, I wanted to know what to expect!

Vic Romano

I get about the same as you 17.5 on the highway and 14 around town. Only 1200 miles on the odo, i anticipate maybe tickling 20 after 15000miles, but i'm ok with what i get now for such a big unit.

Hopper

Well, I brought the '08 home to Denver today from Floydada. I was nicely surprised. Got about 19.5 MPG. Made the 538 mile trip in less than one tank of diesel. I would have had to stop in my '03 to refuel along the way. My '03 averages that trip 14.5 to 15.5 MPG.

bigvick

I have 20" wheels and a canopy... 7800 miles on my truck, and I cant get over 12-13mpg outta mine... Ive gotten up to 15mpg on the freeway doing 60mph driving like a grandpa, but that goes down as soon as I hit an incline... The drive to the dealer and back going 70-75mph on average I got 12.5mpg...



Ive been into the dealer several times (5) for CEL's, Reflashes and the Recall, and twice more after oil changes where the oil change required warning came on. Ive already had the oil changed twice, and its still coming on after 500-1000 miles after the oil change...

I would kill for 15-19mpg... My brothers 05 5.9 dually manual gets 22-23mpg even when towing...

When I towed 8,000lbs trailer I was getting 7mpg...

RocketJohn

well you are are more up in the air with the bigger tires... and you have some extra weight with the bigger wheels and camper... that could be some of it...

fflarry

I just filled up and got 15.9 hand calc with a gps...mixed city and hwy.

RocketJohn

I recommend tracking your next 5-10 tanks to get a real sense of what its returning... one tank won't fly...

CHOPPER ROB

I have never reset mine since day one. I have 12,700 miles and its reading 11.9. I drive town highway and tow approx. 11,000lbs twice a week. My 03' got atleast 2-3 mpg better, but horsepower went from 305 to 350 and torque from 555 to 650. I would love to know what these motors would get for mpg without all the emission gear. I do love this motor though, she just pulls and pulls in any gear...

glowball

I'll bet a $1000 no truck gets 22-23mpg towing. So don't let that beat you up. I don't know anyone getting that kind of mileage not towing out this way.

Scotty

I log a lot of miles. I am running a long bed MC 4x4 dually and average 70 mph or just a shade over that on the hwy. Just did a 5300 mile round trip and I netted 10.2 loaded from Indiana to Vancouver Island. I saw higher and lower numbers on the overhead because of mountains and/or winds. The overhead on my truck is low about 3/4 mpg.
The empty part of the trip netted me 17.2 with the same fluctuations on the overhead...saw 13 and up to 23 on the loooooong downgrades in the mtns.

Something else I stumbled across. I run TOYO M55 17's and was running at 55 psi rear and 60 front. Compared to my 07 5.9 I was running up more miles per trip on my mileage sheet with the TOYO's. I put them up to 75 PSI all around and now I log less miles then the 5.9. For example; My run from Hudson WI down to Goshen IN and back to South Beloit WI would be at 1156 kilometers.
Then, with the TOYO's aired at 55 I was logging 1192. give or take a few K I thought maybe the tires are shorter. After doing the psi to 75 I now log 1136 K. Sometimes its out by a few K but thats due to a pit stop or two.

I also tried a wing on the truck. I did four trips with it. FLAT empty and up loaded. I have done two trips without the wing and I gained 1 mpg with travel trailers, stayed the same hauling 5th wheels and...no difference empty even though the wing did stick up a bit when flat.

I spoke with the dealer I bought this from when we did the recall. He had a customer in there that said he gained a solid 2 mpg by dropping the muffler. I heard a truck without a muffler and the change in sound is not much different.

Apparently theres a few more mpg in these motors when the smog stuff is trashed but since we get checked for emission components from time to time...mine needs to stay on there.

I also wonder if the auto and a 410 would do better since the engine does rev several hundred rpm lower then my 5.9 did.

Scotty

tmcblane

Here is an update over 4 years since I posted last here. I get 10+/- 1 mpg still towing the full max load of my CGWR. Normal driving has not really changed and get about 13. Have just about 50,000 on truck but it has been virtually trouble free