im getting 10-13 empty and 8-11 towing a 3000 lb trailer... the dealership says that is not right and it is going back in thursday...

 

I only have 400 miles on mine, but I am getting 14 around town and averaging 18.5 on the highway. I got 21.8 on the frreway (reset the meter while at highway speeds) coming home today. All of those are empty though.

 

Yeah, that sounds like a problem.

Are you using your overhead to measure that? If so, it's REALLY a problem!

Stupid question, have you reset your overhead and monitored your mileage?

I'm getting about 19 in town and 20.5 highway (Overhead) Empty.

 

yea that is overhead and I have tried reseting it several times. thanks for the help. this trip to the dealer is gonna SUCK...

 

Don't trust the overhead it lies!Mine is off by 2 mpg.

 

igotyourgoat,

Is it a 5.9 or 6.7? The 6.7 will get worse mileage than the 5.9.

If it is a 6.7, it is at the very low end of what I have seen, and there appears to be no rhyme or reason on why some 6.7 get worse than others. O Yea, what are your gears?

You might want include your engine in your sig.

Stealth

 

I've read in more than a few instances where the 6.7L's have gotten better fuel economy towing.

 

Usually, the overhead tells you you are getting BETTER mileage than you actually are.

Yours tells you you are getting WORSE than actual mileage??

 

A little over 400 miles here.....empty so far has been hovering around 13.6. The highest so far has been 16 on the highway. I'm expecting it to climb over time.

 

I had posted this on another thread.This truck is new with only 1300KM's.

I last got 22.3 miles per Imperial gallon on a 400KM run. It was Highway . My first run on same road was 18 miles per Imperial gallon. Both runs were controlled and on Cruse Control at 110Kms/65 Miles/Hr. I am pleased with last results.
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sorry it is a 6.7.. forgot to add that in my sig. BUT I am in the 6.7 forum right?

 

Hey .I understand .My truck now has 10k miles on it .it's a 2007.5 2500 with a 6.7 a/t and 410 gears.The first three weeks I got 9-10 mpg. I was sick,now after a a new turbo and a bunch of flashes it started to get better.At 9500 miles I changed the fuel filter and oil , then went on a 250 mile road trip= 19-21 mpg .more recently aroun town 14.5-15.3. I have checked my overhead against a calculator always .2 to.3 diference.I hope this helps.

 

Your truck is like mine only I have the G56 dually and I get the same milage as you pretty much only my towing can go up to 20,000 lbs. My truck also has a tendency to not feel like pulling to full strength and just getting by. I am now gwtting ready to trade if in for my wife and I am going to fix up the 97 and us it as it gets 18 mpg empty and can out run the 07 empty or loaded

 

The night I bought my truck I have a 290 mile trip home and got 18.9 mpg going 80 mph. Around town between 13-15 mpg and highway still upper 16 to 18+.

 

I have almost 10k on my 08. My average mpg is around 13. Towing I now get 11.5 and used to get 9-10. Empty I get 14+. One highway trip so far and I made 17.3. All those are on paper I do not use the overhead, just figure the better it reads the better my mpg's but do not quote what it says. The overhead was way off when I got the truck, but now it is much more accurate, usually within a half mpg, when I got the truck it was off by about 2mpg's. This truck is beating my 01 6speed 4.10 geared truck across the board both loaded and empty. The 08 is bone stock and will match my 01 (Edge Juice, Industrial 90HP injectors, HTB2 62/12, Helix 2 cam, BHAF, 4" turbo back etc) towing the same trailer, and in the 01 I lived by the Pyro, now I just set the cruise and if something breaks it is DC's problem.