One thing I noticed is a difference in fuel quality when it came to mileage. I live in MN and will consistantly get 18-19 mpg during normal dirving on the highway (65-70 mph). When I would leave the state and start using fuel from south dakota or wyoming my mileage would drop to 15-16 while driving the same speed. When I returned to MN the mileage would come back up to the normal 18-19 mpg. My truck has 17,000 miles on it and the mileage started to improve around 12,000 from 15-16 to the 18-19 that I get now. Maybe this is impossible but I think this may be a reason for the incosistant mpg's throughout the US with our trucks. I have seen as high as 23.5 mpg while driving 55 mph and running power service (gray bottle) in every tank and new fuel filter every oil change (7500 miles)

I have spoke with with our fuel guy on several occasions and he states that most of the ULSD that he has been seeing is around 5-6 PPM sulfer because the refineries are not taking any chances in getting anywhere near the 15 PPM max. He states that some fuel may giver better MPG's because some of the fuel may be closer to the 15 PPM max but he didn't think it would be very noticable. He tells me for the most consistant mileage is to use a quality additive and change the fuel filter on a frequent basis.-Frog

 

my 07 was getting 14.5 in the city. 19 highway. at 5k miles on it i towed about 10k pounds for 1k miles geting about 11mpg. Since i unhooked that trailer i have been getting much better mileage. In city now i get 16.5 to 17. Havent had a long highway trip yet to see what its at there. I think that tow may have broken her in some. Maybe my smarty has something to do with it also. When i towed i was on setting 1. Now im on setting 3. Havnt been stock since i bought it.

 

i think that THEFROG is correct. i find a -BIG- differice between statoins even in the same towns, letalone the same states. one stations fuel will cause way truck idle rough and get about 16 mpg, anothers fuel will idle smooth and get 19 mpg, both city driving and on additives. even bought a tunk of fuel that showed 13 mpg, truck ran verey bad. i have found one station that has the best fuel in may area and i stick with it. i get 19 city 22 highway.to those in the area,cheveron in canby or, the best in 50 miles buy fare.

and as a side note, my last truck 96 12 valve stock, on b99 i could get 26 highway. i hear a lot of people saying that bio will show 2-3 mpg lower? it got more power to. em i crazy?

 

guy I work with said he got ~15-16 new and can get 21 on the highway-he`s got 110k miles now.

I get 15-16 with 50k miles, I hope it goes up with the parts I`ve ordered.

 

18-19 mpg around town

21-22 mpg highway @1800rpm

13-15 towing flat & hills

picked up 2-3 mpg past 15k miles

03 ho 6spd 4x4 with 315's