Does any one know why I'm getting only about 10-11mpg, even if I drive it nice, no matter what setting I put the edge on, Is anyone else getting this low of mpg, truck has about 8,900 miles on it now, It was getting around 15-16mpg until about 2 weeks ago, I've tried other gas stations with the same results

 

Not sure, but i think there is a dealer reflash for some 06 and 07s for poor fuel economy.

 

has your stations switched to the winter fuel? Just a thought

 

I bet they did change to winter fuel

 

That will sure put a dent in the mileage

 

that much of a change , i get disapointed if mine is below 20.0

 

This is really going to hurt my trip to new hampshire on thursday, 2000 miles one way

 

i only get 12 mpg. i havent got the computer reflashed yet.

 

I really dont want to take off all my edge stuff just to get the computer reflashed but I guess I should, does this really help and does anyone know what I need to ask the dealship for?

 

ok, so alot of people with the newer cummins 5.9L claim to be getting 20+ mpg out of their rigs. I have a 2007 with 11k on it and never ever have seen over 17.76 mpg hand calculated (not overhead). Now when I got 17.76 mpg it was a freeway trip to Oregon of 65mph + the whole time. The overhead was reading 21-23 mpg the whole time. I have a hard time believing the cummins is ever getting over 20 mpg hand calculated. I added a home made air intake and a quad zxt chip box and it got a little better, but still no 20+ numbers. Is everyone thats claiming this going off what their overhead says?

I complained about mileage on my 2007 5.9L at about 6k and they indicated they were un-aware of a reflash for mileage or to correct the highly inaccurate overhead reading. Only thing I have got them to somewhat fix is adjusting my speedo from reading 3.2mph too fast. Now its only off about .8 mph at 70 mph on the freeway.

 

I'm amazed at all the people who 'can't figure' mileage..... I hear all the time about how great they get. One of these trucks can't get 28 MPG no matter what you do (Stock, under everday 'normal' conditions). A F-350 crew cab 4x4 with a 460 can't get 18 MPG either (The list that I've heard goes on and on).
I've had 3 3rd gen CTDs now. The first two did get pretty consistently in the 18+ MPG running around empty and easy. The first had a best of almost 20 and the second had a best tank of 20.6 MPG. Since tanks before and after these 'best's were right in there for what I expected to get; I feel that this best number is accurate. The averages for both of these were usually around 18 or 19 MPG empty.
I have no explanation for why this new truck won't get much over 15 MPG in the same easy conditions. I feel something is wrong with it; but, you know how much help I can get from the dealers......
I also have to mention that I think I am pretty careful calculating my mileage numbers. To do as accurate of a job as possible, you have to:
1. Verify your odometer is accurate (Or figure out how far off it is!).
2. Keep a log of fill ups with as much info as possible.
3. Fill consistantly to the same level everytime.
4. Drive as consistantly as possible.
If anyone needs help calculating their mileage numbers; just ask. I have an Excel spreedsheet I will share with all......
hth,
Dan

 

Actually, Tim got 29 drivind 55 with a tail wind going from Amarillo to Denton(downhill). Best I've using your calculation methods is 23.7(summer blend fuel).

 

I'm betting your injectors are sticking, that's a big dive on mpg. How's the cold idle?

 

I just had the reflash done, it worked! Instead of my overhead(20+) lying it now shows 13.

 

I too do not get the awesome fuel mileage some claim.

But, for a 3/4 ton truck I can't really complain much.

On the interstate I'll usually get somewhere between 16-17 mpg. The overhead usually reads 17-18 mpg.

I just returned from a 500 mile trip and re-fueled this morning and hand calculated 15.97 mpg. That was unloaded running between 75 and 80 mph.
(I just can't make myself drive 65.)

Around town I'll get about 12-14 mpg.

I have 9500 miles, so I'm not sure how much these numbers will improve.

I'm not aware of the reflash some of you are talking about. What does it do?

Are these numbers to low?