The wife and I just did a 2268.5 mile RV trip to Florida pulling our 12000 fiver. The 2268 was the total miles towing and not towing. Going down with the fiver I got 9.2 mpg towing at 65 mph on interstate I95. The total trip on the DIC was 10.7 mpg. I have checked the DIC and it seems to be right on the money. I have reset the DIC since I got back and everyday driving getting around 18 mpg. The truck now has 11,000 miles on it with no problems. I got around two mpg better with my old 03 Duramax. The old truck was a ext cab with 2wd as the new one crew cab 4wd. I really like the truck but I see post with better mileage.
Tom

Its new...they dont fully break in until 80,000ish miles...The mpg's only get better. If your really worried a small tuner will add about 2mpgs

Yeah, and if you were using ULSD Fuel instead of the stuff from 2003, you can expect lower mileage figures. The new fuel is a big part of mileage reductions, same with gasoline and E-85 ethanol.

Just got back from vacation in Flordia. 07 2500LBZ 2000mi. Im from Pa. Hauling 16ft box trailer loaded to the gills[2 dirtbikes,Harley big toolbox ect,] On the way down though the moutains @70+ got little better than 11mpg. After the mountains @75+ Almost 12mpg. Once we got there no trailer 75-80 driving with heavy foot 17.6. I was very impessed with the power. I can count on one hand how many times the tranny had to shift up those mountains. Does anyone know if putting 500ppm sulfur will hurt the engine? Alot of places down south only have that. Didnt seem to have any ill effects. I love that truck!!!

An '07 Classic can take either fuel type but I doubt you got 500PPM anywhere as by law it was ULSD as of October. All 500PPM should have been gone by now as the new '07's are out and I really doubt you have one of those. Very Rare and only the first ones are showing up on the boards.

An '07 Classic can take either fuel type but I doubt you got 500PPM anywhere as by law it was ULSD as of October. All 500PPM should have been gone by now as the new '07's are out and I really doubt you have one of those. Very Rare and only the first ones are showing up on the boards.


Not true. You can still & could still find the 500 ppm up to 2010 or 2011. I have still used it from time to time. Some of the bigger station carry both.

Took my 5 er from the San Antonio area down to lower south Tx, ( McAllen ) this past week. 280 miles oneway. Had ULSD in it. Got 9.1 mpg @ 68-69 mph. Filled up with LSD, that`s all I could find down there, and started back at same speed. Still only got 9.0 after fillup at 140 miles. Dropped back to 65mph the rest of the way and wound up getting 10.8 mpg. Could 4 to 5 mph make that much difference ??
I wonder if it would have been better yet if I hadn`t taken time to convince a couple of winter vistors driving PSDs who were also pulling 5 ers, not to challenge a Dmax. ;)

Anything under 1800 rpms will maximize the fuel mileage in my opinion.

Not true. You can still & could still find the 500 ppm up to 2010 or 2011. I have still used it from time to time. Some of the bigger station carry both.
Yeah you can find both the 500 is red though:p: . Mine gets 14mpg hand calculated. Empty, pretty much highway/city combo. 10-15 min warm up in the mornings.

Yeah you can find both the 500 is red though:p: . Mine gets 14mpg hand calculated. Empty, pretty much highway/city combo. 10-15 min warm up in the mornings.
You can still find LSD at many stations, and it is not red.

I got about 9.4 towing 7500 lbs at 75 when the truck had 500 miles on it. I'd say you did pretty good.

Just finished a round trip from SE Wisconsin to Florida pulling a 34 foot fifth wheel - 3350 miles total. Behaving @ 67 - 68 mph we averaged just shy of 12 mpg. Truck turned over 10,000 miles about 150 miles into the trip. Most fuel stops were Flying J with a couple Loves and locals mixed in. To my surprise, a couple fuel pumps said LSD which seemed to be the lower priced independents. Those tanks didn't result in any mileage variation greater than all other fills.

Just finished a round trip from SE Wisconsin to Florida pulling a 34 foot fifth wheel - 3350 miles total. Behaving @ 67 - 68 mph we averaged just shy of 12 mpg. Truck turned over 10,000 miles about 150 miles into the trip. Most fuel stops were Flying J with a couple Loves and locals mixed in. To my surprise, a couple fuel pumps said LSD which seemed to be the lower priced independents. Those tanks didn't result in any mileage variation greater than all other fills.


How much did the trailer weigh?

You can still find LSD at many stations, and it is not red.


Exactly. Thanks The bigger stations still have both & non-red type.

Dieselwannabe - Didn't scale it but my guess it that the trailer weighed between 10k - 11k.

I got averaged 14 towing 5500 lbs at 60.

getting 19.5 not towing with a diablo set on 65hp

I went to Mo and Il last march and put 1960 miles in 3 days driving 79 mph, 4 people in truck and 600 lb propane tank in back and av an even 20.0 mpg.

Take muffler off of 06 and you will get 1-2 better.
and no noise.