Hey guys,
I have read several posts on mileage and noticed most were on 2500 mpt so much 3500. My 06 is not making me happy I am only pulling 14m.p.g and that is driving maybe 30 miles one way with no stop and go traffic. No stops lights where I live!! driving no faster than 60 no idle time. I am trying ti get the best i can on fuel. i use a cleaner every tank full. My 01 done so much better. Is the 06's w/ auto & 4x4 that much worse on mileage? i hear you guys pulling 18 & 20. I would love 18. I hand figure my m ileage I know that idiot over head sensor is not accurate. I have stock tires. run top air pressure. I even hooked on my heavy trailer pulled it hard. Then checked after running empty. Any suggestions? She runs good idles smooth. filters new. Thanks for any suggestions

 

SORRY Dude, ..... Do you have the 4.10 Rear? Make sure that brakes are not partially engaged. Fuel system cleaners are not helping you at all! I can 100% state that when I added anything to my fuel (cleaners, cetane boost, 2cycle oil) I got worse mileage. This time of the year you have winter fuel and will always get a little worse than summer time fuel. If everything on the truck checks out it has to be your elevation/terrain, fuel, or a slipping tranny...... Good Luck!

 

No its not the 410 gears. wheels turn free, no brake drag. Tranny rebuilt, no problems there. I know about winter fuel. But did not think it would make that much difference. terrain fairly flat here in indiana.

 

Whew Indiana....... are you running B-20 Fuel??? Some of these ol cummins just never get good mileage and some get great. I know that I drove 3 Identicle trucks off the lot in 06 to see which one got the best mileage. 2 were at 17ish and one was 18.5ish....I bought the 18.5-ish one ..... The only difference in any of them was the color and the one I bought had the bug shield???? Hmmmmm could the bug shield be it? I doubt it but hey something made a difference.... When I tested them I had them full, drove 50 miles with each, and filled them back up on my dime. Dealer did not care because I sell a good amount of trucks for them and have bought many my-self ..... My fathers 05 3500 4X4 Dulley got 18 all day every day.... 13 MPG pulling a 27' 4500 pound boat....then trailer...then motor ect ect......

 

Something sounds amiss on your truck. In my 06' my best mpg is in the high 17's with about 80 hwy/20 city, going no faster than 63 mph, (which is 1900 rpm with a 4.10 rear end and stock tires). Normally I see about 15 - 16 mpg in 50/50 driving. My normal commute to work is only about 5 - 8 miles, with a few stop signs and stop lights here and there. Most of my "city" driving though is more like country roads.

 

i'm around the 15mpg pulling heavy loads, IMO the its hard to beat mileage on 2nd gens when pulling heavy loads

 

It probably won't get better, that is around what I get most of the time.

 

My 06 Mega Cab Dualie 4X4 Auto with 3.73 gears gets 14 around town, 15 on the highway and 10 towing 8K pound 28 foot enclosed trailer. Runs great and it is what it is. My old 97 2500 4X4 Auto Ext. cab with 3.54 gears got 17 around town and 23 on the highway. Towing on highway was 14.

 

The truck in my sigline has averaged 15.2 for over 7 years......Ben

 

So I guess from waht i see from you guys its not to bad. I just read all the guys saying they are getting 18 20 m.p.g must be with the wind at their back. Guess ikt wont get the mileage of my 01. Thats not good. Maybe summer fuel will be better.

 

Granted mine is a 2500, & my Smarty is on SW9 all the time, but I only get 14-15 ave too. I thought it was something wrong with my truck, but I looked @ my hrs, vs. miles, & I usually average only 30 mph. I thought I had about even hwy/city miles, but after seeing that I don't think so. I have had as good as 16.5 mpg, but that was on a trip over the mountains in winter with a 1/2 hr stop for avalanche controll. So I think I'm getting about 18+/- without mountain passes, & headwinds, etc. Just never seem to get lucky with travel around here. Allwys a mountain or two to cross, & headwinds.

 

I believe there was a flash upgrade for some of the 06,s with poor mileage??

 

Hey eot, I noticed you didn't show your mileage on the truck.....I know my '03 is a little different animal than your '06 but my mileage wasn't all that great until I hit about 50k then it went up. Until that point I was only getting about 14 mpg but now, even with 270k, I can still get right at 20 mpg on the highway. Just something to kick around. Hope you get it figured out.

 

05 gets14-15mpg empty. 9-10mpg towing 15000lb 30foot 3 Axel enclosed trailer. Does not seem to care if I run 55mph or 70mph. Unbelievable grunt but you pay for it.
92 is 20mpg empty and 12mpg same trailer but it really struggles, 65mph would only be on the level no wind(maybe tail wind).
Clark

 

22 empty and driving it easy between 1,100 and 1,800 on the up shifts. 3.73 gears, runs about 2,000 at 62.5 mph. 55 / 40 psi in the tires empty. They wear flat accross. Cruise at 65 or less on the hwy and 50/50 city / hwy in Tennessee hills. See signature for rest of specs. I'm going to be adding a Smarty soon.