well then i`m stumped, reading what yu are all getting for mileage. i`ve taking my fuel ups recorded them all , and i am getting 15/16 in town and 20/21 on the highway , plus mine is awd , i`m thinking i get better milage due to the new bigger motor , performes way better than the old one before new rebuild....breathes better ,more hp to move her 5000lb big ***..tires and gearing ,,, and tune does help....i didn`t use my old 01 block i used a 03 5.9L bare block that had only 1500 miles for my base.....

 

i have a 99 d with the 5.2 with 137,000 miles on it with a simple exhaust upgrade and a diy ram air intake off of hydra's idea with the flex tubing and i drive 130 miles round trip to work daily and i get a little above 20mpg hwy and 16 city. i just did a simple tuneup plugs, wires, oil, trans, and filters. i get on the road and set my cruise to 72 or so which is my sweet spot for mpg's.

 

I can get 17 or "almost" 18 out of my 5.9, but not on a regular, consistent basis. I dunno, maybe those are just the days when the wind is at my back.....

Right around 15.5 is what I would have to give if you asked for a consistent number.

 

Agreed. That's about the number I get on a regular basis. Typically I'm getting around 13 though since pulling a 7,000 lb trailer has it ups and downs. LOL

 

Hmmm.... That would be about what we get when my wife and her lead foot are behind the wheel, no need for a 3.5 ton trailer.... LMAO

(God, I hope she doesn't see this post.... )

It's a bit weird. I'm the one who likes to get on back roads and go nuts. Fishtailing, donuts, mudding, busting snow drifts, etc.... But when I get on the normal highway, I'm the one who drives like a granny.

 

I completely understand. When i'm out on the interstate with no traffic around anywhere I have cruise set at the speed limit but when I get into the city with all the traffic an stupid drivers I get a little rage and start running 80+. I can feel my blood pressure rise too.

 

I am not putting in enough miles right now to give timely attention to the TB test right now- but will definitely keep that in mind a few tanks down the road.

It sounds like I might be a bit low, but not horrific. I actually think based on one of the posts that maybe I am going TOO SLOW on the freeway! I think I am setting cruise at 65 or so. I will see what my RPMs are and post that next time I head out!

I am a little chubby too- but not 7000lb trailer chubby... so there goes that theory!

 

Okay, so I am "instinctively" doing about 68-70 on the freeway and between 1800 and 2000 RPMS.

That sounds a bit off from what I read. Taller gears? Do people do that? Tires are 31"s.

 

if you have the 3.92 gearsin the rear, that sounds about right

 

I have been averaging 12.5 mpg since I cleaned my tb. Before it was around 13.5. How is this possible? I reset the pcm and keep up on all maintenance. I know a big part of my decrease was going to the bigger more aggressive tires. But going from 17 mpg before the 100,000 mile maintenance with the new tires to 12.5 mpg is kind of ridiculous. Yesterday I refilled and calculated my mpg and got 11.7. I don't have a lead foot anywhere near like it used to be. I don't need anymore speeding tickets or to lose my license again.

I drive like grandma on the expressway, 65 mph and engine rpm is about 1500-1600 and get about 15 mpg.

My ford gets 6-7 mpg on a good day going downhill not touching the pedal. Open up the 4 barrel and it goes from mpg to gpm!! Thats why I got my D, fill up once a week rather than once a day! LOL