Mallard

I need some advice. I have an '04 with the 5.9 and I am only getting 11 MPG. I've taken it to the dealer and they say they don't see anything wrong or any needed updates. I have 10,000 miles on it and everything is stock, except 285 BF Good tires. I pull a small 16 ft. enclosed ATV trailer.

My last truck a '99 with the 5.9 set up the same (only mod was a K&N filter) was getting 17 MPG pulling the same trailer.

Does anyone have any suggestions of what I can do to get better mileage ? I'm considering intake and exhaust mod's but only want to do it if it is guaranteed payback without too much added noise.

BiggRigg600

Is your truck an '04 with the 305/555 engine, or is it an '04.5 with the 325/600 engine? You can tell by looking at the sticker located on the driver's side of the valve cover or it should also be listed on your window sticker if you have it.

So far, there seems to be quite a few of us experiencing poor mileage with the '04.5 models, however there are others getting decent numbers as well. The cause for the poor mileage in some trucks is still a mystery, but the members of this board (including myself) are relentlessly seeking a solution. By the way, I've read several times here on this forum that changing the exhaust and/or intake will do very little, if anything for your mileage (if someone else knows otherwise, please feel free to chime in). So far, all indications appear to point towards a fuel system/timing issue that is causing the problem.

There are numerous threads on this subject so look around. Here is one thread that at least sounds promising... involves reflashing the ECM, and this guys is getting much better mileage now. https://www.dieseltruckresource.com/...threadid=45474

Good luck!

Tomtt

Took mine in today and they checked it in shop and drove it with "scanner" hooked up and said all was the way it should be. There were no TSBs or updated that apply my truck.
I was told they have new updates comeing in everyday and to check back.
When I left the motor felt a little stronger, it was only my imagination and the fuel mileage still SUCKs, 13.4 mpg around town driving very easy.

It has 6500, miles many with a 5000# trailer.

Mallard

My truck is the older '04, not the new 600 engine. My local Dodge dealer ran the VIN # and said no updates were available. Would a Cummin's repair shop be more knowledgeable ?

stevenknapp

Would a Cummin's repair shop be more knowledgeable

I've wondered the same thing. Anyone tried taking their truck to a Cummins shop and just paid an hours labor for diagnostic work?

SHINDEN

Cummins shop does not have appropriate hardware or software to connect to our dodge trucks, in the way they would attempt to solve the problem in the dark charging $100 per hour.
I do think that they would be able to correct the problem eventualy but at what cost, I head my truck to Cummins shop but was told that DC does not want them to look at them, that is why they do not sell them hardware or software.

Regards Jack.