My dads stock 06 was getting the 15-16 and he was disappointed after having several 2nd gens that got better so he talked to his his buddy at the local dealership and they reflashed his ecm and it is getting 22-23 on highway unloaded now so don't know what all it changed but might work for you.

 

can you find out what month and year your dads truck was manufactured? mine was 5-06 and supposvely have this flash. If your dads was manufactured eariler that would make sense.

 

On Saturday I had a ton of rock in the bed and took a short 381.4-mile drive on state Hwy’s and even through several small towns (I wanted to clean up the injectors from slow driving this past winter) and the truck only used 19 gallons of fuel and that equals 20 mpg. Oh I did also pour in 16 oz of Lucas when I filled up so that may have helped the mileage some. In my truck when hauling or towing it gets its best mileage between 55 and 62 MPH.

I’m a firm believer that how an engine is broke in makes all the difference in how it will do later on in its life for mpg. If you load them up and run them either hauling or towing weight is the key. I put 1000 lbs in the bed of my truck when it only had 1150 miles on it and my wife and I drove it non stop for 33 hr’s except to fuel up. Semis do the same thing they load them up to 80,000 lbs and drive them; as it is the best way to break in a diesel engine, make them work hard.

JMHO

 

I agree with DBLR. I think alot has to do with how you brake-in your engine. My last fill up while running empty was showing 19-21 on the overhead. My hand caculations at the fuel pump divided by the mileage driven said I was getting 20 miles to the gallon. When we bought our truck in Saint Louis and we babied her until we got home. Then at work the next couple of weeks I loaded the box up with about #3000 of paper and made some copy paper deliverys since our paper suppliers truck could not get into the alleyways behind the stores due to construction. Later I pulled #10,000 trailers four or five times out to the local coal mines and my father in-laws #4000 house trailer to my grandparents house in North Dakota for a family reunion.

Any time you have more horsepower you are going to use more fuel. As it was said before our trucks are even heavier than some of our predeccesors due to the body design of the quad cab, the AAM axles, the supposidly beefier transmissions and the boxed hydro-form frame design. Gearing also has a lot to due with mileage and this is why I decided on a manual instead of a automatic. to which I have a closer shift spread while keeping the truck in the powerband while shifting. And yes, the so called third injection event is another reason. Even though the pre, main, and third injection event is one continuious injection and not three separate injections.

Another one that is hardly mention is the fact that when the US shifted to ULSD (ultra low sulfur diesel) the new refinery processes has lowered the BTU (British Thermal Unit) content of diesel fuel slightly. Even though they claim to have added an additive to raise the cetane rating.

I will be very suprised if a 2007 daily driver in city traffic with the particulate trap will deliver good mileage compared to a daily over the road truck or previous model years. Exspecialy since, the 07 in traffiic will idle up to increase exhaust temps to burn off hydrocarbon caught in the particulate trap. Which will result in more fuel being used.

I also think it has to do with the intake air volume. If you can get more fitered air into the engine the truck will have more power and use less fuel.

Shawn

 

I do not believe HP= poor MPG. My 01 was daily driven at ~450 RWHP and weighed ~8000 pounds. It would get 20-21 at 70 MPH. My 06 has a hard time getting 16 at 65 mph. It only has 4K on it right now so who knows if it will get better. I do know I'll be hooking up to my trailer with a loaded derby car on it and dragging that around for a while in hopes that it will lead to better MPG.

 

There's also a huge difference between G56 owners and NV5600 or 48RE owners. The final drive ratio on the highway has us G56 owners at a major deficit from the get-go. 2200 rpm's at 70 mph is gonna burn some diesel.

Also, the new fuel having less BTU's is an issue. Same thing with biodiesel. I've run B100 and lost 2 mpg! I've found that my mpg varies greatly on the batch of fuel I get (petro or bio). Cetane doesn't seem to help me much in regards to MPG. It helps in cold starting and and other cold running issues. "The cetane number of diesel fuel is an indication of how easily diesel fuel will ignite under compression." It lowers the flash point / increasing combustability but the amount of energy in a gallon of diesel is measured by BTU's as stated above. "A BTU (British Thermal Unit) is defined as the amount of heat required to raise the temperature of one pound of water from 60° to 61°F at a constant pressure of one atmosphere." People confuse these. So basically the more BTU's, the better MPG you're gonna get.

Here's a staggering (slightly off topic) statistic:

"In 1966 the going price of a barrel of oil was approximately $3.25 while 40 years later the price is more than $60. During this forty year period, though, the price paid to farmers for a bushel of beans, soybeans that is, has only doubled."

 

I'm not convinced that break-in is the full answer. My truck's MPG went as follows:

1. Off the showroom floor: 13-14 MPG city, 19 HWY
2. Towed heavy after 500 miles to help break-in
3. After 8,000 miles: 15-16 MPG city, 20+ HWY
4. After February (ULSD came out, plus winter blend): 13-14 MPG city, 19 HWY

I'm right back to square one with this crappy fuel.

 

In my truck my best mpg with a load or towing is between 55 and 60 MPH and any time I go above 1750 RPM's I know my fuel mileage will start to drop. I've talked to several people who also get their best mileage at the same speeds as I do.

One other thing about breaking in your engine is to do drives that are 3 hours or longer along with the weight. When mine only had 125 miles on it I took it for several trips (empty) of 3 hours one way. The shortest drive time I took on my 33 hr break in trip was 2.5 and my longest was 6 hours in between stops for fuel. Also during my break in trip the engine was never off longer then 15 minutes so as to not let coolant cool off more then 20 degrees. IMHO it's a combination of weight and hours driven non stop that helps break in a diesel engine.

 

Hey All,

You all have it all WRONG! Here's the real scoop.

Kickbacks

Back in the early to mid 90s diesel trucks where not as popular as today.
Some corp big shot sees trend, talks to oil producers, fattens his pocket by
having the computer engineers work the control code so they get less mpg.

Corp big shot now has 40,000sq ft home, private jet, and has retired early and is laughing his butt off
Oh and he drives a Toyota hybrid!

Cheers

 

Sorry I just had to.
Actually my '07 is my first diesel, so I have nothing to compare to.
But it does get better mileage than my '05 F150 gas!

 

It should get better. I just went past 16,000 on mine. Off the floor it got 13-14 until I went on a trip to S. Dakota with a '66 Comet on my trailer. Then it started to show 15's until winter fuel/ ULSD. After the second tank of summer and 16oz's of power service at every tank, it Just gave me 17.78 calc'd with raw fuel in the neck. That's unloaded at 62mph with the cruise on, 40 minute drive to and from work every day. I think on a long trip uninterupted it would tip into the low 18's. I'm happy to sat the least.

 

If I can haul %#& in my one ton 4x4 mega cab and still get 16-19 mpg whose complaining, not me.

 

Here is a couple of TSB links regarding the Ram Fuels systems.
Hope these work.
This first TSB link talks about fuel quality.
http://dodgeram.info/tsb/2006/14-007-06.htm
This TSB talks about how the overhead on 06 and newer trucks do not reset due to the vehicle enviromental conditions such as going up hill or down hill during a reset.
http://dodgeram.info/tsb/2006/08-020-06.htm

Shawn

 

That's surprising, we have nearly identical trucks. 03 with the rare 5 speed and no cat!. I bought mine at 92,500 miles and got over 18 driving home from picking it up, at about 77-80mph. I get 22-24+ regularly. Hand calculations come in 1-2 mpg less most of the time, but still, that means i'm still getting 20+ at least 90% of the time. I drive pretty civil most of the time. And as for the high hp = poor mileage....NO. I drive around with my TST off most of the time, which leaves my downloader on performance - that gave me 379 to the wheels and I have always gotten the same mpg numbers.

 

I am in the process of thinkin about a new truck. I hate to get rid of the ole 92 and to tell ya the truth I just may not.

In lookin at the new trucks I see (and maybe wrong) that the 4x4 system is not like my ole 92. I have manual locks while the newer trucks seem to use the same system I have on my 94 YJ. The differential and axles on the new trucks are moveing all the time. This takes fuel and power along with constant wear on the front end. I wish they would realize the old free wheelin system is the way to go and stop makeing these push button trucks. I guess the mph problem is the emissions and increase in power but they don't seem to care about the milage. They just don't get it. They don't care but we do!! Or at least (I) do. If they didn't use the "live axles" and went back to the freewheeling I know I would be a lot happier and the milage may get better. It doesn't take much to kill your mpg. There are no dought other places that could save fuel. In stead of more cup holders I wish they would find them.