Very poor MPG?

[joegayle]

Hello all,
I have a 2004 Cummins with 170,000 miles on it. I am getting between 13-15 MPG empty down to 9-13 with a 13,000# trailer. I have asked a few folks who drive similar rigs about their MPG and then they are surprised at my poor fuel economy. It blows black smoke when I get on it and on occasion, I also occasionally smell diesel while idling. The mileage has been like this since I got it in 2008.
Also, for what it is worth, there is a little hiccup when it shifts at around 45 miles an hour.
Thanks,
Joe

 

[joegayle]

Would anyone have suggestions as to better fuel economy?

 

[justin13703]

Honestly those numbers don't seem far off to me

 

[Jimmy68]

I got 17mpg in my 07 3500 5.9 Cummins 4x4 6 spd manual

 

[SilverStreak88]

The black smoke does nothing but over fuel the cylinders. If you smell diesel then you need to start looking for a fuel leak somewhere.

 

[ST-8]

If you been getting the same mpg for 7yrs why **** with it now? My 1500 gets closer to what you get loaded when it's unloaded

 

[justin13703]

If you been getting the same mpg for 7yrs why **** with it now? My 1500 gets closer to what you get loaded when it's unloaded

Right lol that's what I was saying, 9-13 mpg while towing almost 7 tons seems fine to me