15 to 16 @ 75miles an hour.

2500 05 with bully dog at preformance setting. also k&n filter

1500lbs of tools and parts, plus a utility top sticking above the cab about 8 in.

not bad to me.

 

My overhead this week showed promise with readings of 14 to 15 , but then I CAME BACK TO REALITY when I filled up and hand calculated a awsome 10.87 pretty darn good I must say for unloaded,never over 2000 rpm cruiser. And yes I know I am a lucky one to be driving a 8000# truck(not a honda). Guess I am better off in this cummins, could be in my gas guzzlin 454 that got 10.5mpg loaded or unloaded. I am shaking in my boots to see my gas mileage in a few weeks when I hook onto my race trailer. Hopefully I will be warm and fuzzy if I can get 4 to 5 MPG

 

dont forget guys that wind speed and direction plays with your mileage to, as i found out. everyday is not treated equal.

you would be surprised what a 10 to 15 mile an hour wind blowing against your truck will do. turn around and go with the wind and pick up about 2 to 4mpg.

also I cant say it enough TIRE PRESSURE

 

I have about 600 miles on mine right now and I'm getting around 17.3mpg. Mine was built in Feburary 06. Pretty pleased right now!!

 

First time poster and new diesel owner adding my .02. Picked up the new truck in Spokane a couple of weeks ago, put 460 miles on it straight away back home to Oregon and got 15.1 mpg doing 70-75 mph w/25-30 mph head wind along the Columbia Gorge for about 3 hours. Hand calculation was in-line with overhead. Since then we're up to 16.9mpg running at 50-60mph and around town. Overall, I'm pretty happy with the mileage, as it's a heck of a lot better than the old gas guzzler was getting.

 

Dang, three hours in the gorge? Did you get lost in the gorge on the way home? Should only take you about 45/50 minutes running the Gorge at the posted limit's. I can run the gorge just under cop level in about 40 min. from where I live. And yes at times that head wind really bite's.

If we could turn off the wind, all the tourists would go home.

 

After driving 8 hours up that morning, it sure as heck felt like 3 hours coming back! At least from the boring part when you hit I-84 at Umatilla. We're on the interstate until the I-205 south exit to Salem at Portland (It's about 180 miles.)

 

Heck I just went on a 4700 mile trip from IA to OR and my over all mpg was 18.3, this inclued a 200 mile trip in to Yellowstone park. My lowest mpg was 17 and my best was 20.3 and it now only has 6600 miles on it. On my trip I had about 900 lbs in the truck bed. All of my mpg is calculated by hand as the over head computer has always read lower than what the calculator comes up with.

Have you tried mixing 8 oz MMO and 10-16 oz of PSD (gray bottle) in your fuel tank to help increase mpg? BTW, my truck is 100% stock.

 

I know very little about fuel additives, so no I haven't tried anything yet. My truck only as about 650 miles on it.

 

I have an 05 that was reflashed today. The truck only got 13.5 - 14.5 hand calc, but I took it in with the complaint that the truck had a flat spot up to around 2K RPM, then would take off, but would bellow black smoke.

I dont know if it is going to help the mileage or not, but it sure is like driving a new truck now. The flat spot is gone and much better acceleration.

I have to make a run of around 2000 miles next week, will see what the mileage does then.

 

Well.... In response to my previous post in this thread, I took the truck in for a recall yesterday and while it was there had them flash it for the auto smoother shifting and driveability improvements (in hopes of getting better mileage). I will say this, the transmission shifts better... or should I say the TC goes in smoother. But here's the kicker, I never saw over 16mpg on the overhead, even when running down the highway at 70mph. After the flash yesterday I reset the overhead and put it back on temp so that I wouldn't drive the truck any different to get better mileage (out of sight...). Anyway, I drove down the highway at 75+ most of the way home and when I got into the city a ways I checked it..... 18.9!

NOW, might be BS based on what I have read so far, so I am planning on checking the hand clacs on this next tank. Should be easy to see.... I never made it much over 400 miles on a tank before. I am filling up today and have no reason to change the results in the test (towing or hauling), so we shall see!

I will post back up in this thread when this next tank runs through. Not sure how long that will take.

 

My '06 was built in february. It's never been back to the dealer, and is totally stock. The first 5000 miles or so I averaged about 16.5mpg city/highway. Now that I have 8500 miles on it I am seeing 18.5 to 20mpg city/highway. This is using a calculator. The overhead display always reads high. It averages between 20.5 and 21.5mpg. I am happy with the mileage, but it still isn't as good as the 609hp first gen.

Mike

 

I have the 04.5 and started out at 14 mpg. I was not impressed. But as I put more miles on it and made it start earning its keep, the mileage went up. The biggest improvement was when I passed 40k miles. Now, at 55k miles I see consistent 19 - 20 mpg. That's combined city/hwy driving.

Ken

 

Well, here it is.... the definitive results (as far as I am concerned) about whether or not the reflash gets better mileage. I just refilled the tank and hand calc'd the mileage. A whopping 14.6. Virtually no difference except that my overhead now reads about 1mpg high, whereas it was near dead on before the flash.

The only difference that I can think of is that the temperature has taken off around here lately, so I have been using my air conditioning most of the time. Before the flash I was using it hardley at all. Meaning that there might be a fuel savings in there, but it probably negligible.... along the lines of 0.5 - 1.0mpg maybe.

Just to be clear, I didn't change my driving habits at all, and this is commuter mileage along with some running around for small items here and there with some intermediate trips on the highway. Basically, the same driving conditions.

Verdict.... no soup for me!

 

TRC51 I feel your pain. I did not believe in all the hype of the reflash either. My truck runs perfect, just poor mileage. Glad I have not done the flash because knowing my luck my truck would run crappy and get bad mileage.