my speedo has been fixed from installing the 315s i've had them on the truck for a while now. I was getting around 400 so miles tank stock and now im getting about 275 to tank. Before i have fill up so i wont loose prime on my fuel pump. I have it set at 16psi it goes from 14-17psi varrys running down the road. It just seems to be sucking more fuel latly dunno proble. It could be my foot . But it just seems there's something odd going on Other day coming work fig i play little bit put my programer on 3 and when i left the stop light my fuel pressure went way down to about 4psi soon as i let out of it jumped back up to 16psi not sure what caused this problem.... I hate say this but im looking get rid of it soon. Not just cause poor fuel milage. I just bought a house and i like have that extra money in my pocket and not have a truck note and fuell cover insurace right now. Later own i plan on getting 2500 crew cab short box. HOpefully!. Might wait they work the bugs out the 6.7l first tho... Think by end week im have the old gal cleaned up and put on ebay or in autotrader. Yall think it be wiser to take the programer off and sale it that way or leave it on there?

 

My DTE (Distance to Empty) is roughly 600 miles. I normally get at least 500-550 miles to a tank of fuel. This is hand calculated...

Larger tires will reduce you MPG numbers. It take extra HP/TQ to turn those larger tires. Not only that but it make you a larger profile in the wind now (More wind drag). It is really common for people with larger tires to lose 2-4 MPGs for larger tires. I'm still using the stock 265/75 R16 and no problems

As for using programmers / enhancement boxes... I've got a Edge Comp and found out you will not get any enhancement unless I run 4x4 or highier. Since 1-3 sub level are defuel modes you will not get any performance boost unless you boost is above the low mark. Now with the Edge comp on 4x4 and using 2 cycle oil in the fuel I've crossed the 19-20 MPG mark many times now!

I keep a full fuel logs book since 20K miles to 107K (current). Ask me I'll post my graphs....

 

what yall think my cummins is worth. its 2001 2500 ext cab short box 4x4 leather seats power captin seat, all power windows steering. tow mirrors, running boards sliding window. its a auto with od just turned 137,000 mark. running 315 mickey thompsons 70% left maybe more, other than big dog fuel system and the edge/juice with attiude its all stock. I looked at blue book low is 13,900, mid range is 15,400 and high is 16,500. If ya can look at my pic's in my sig and let me know. thanks.

 

Well the overhead on my truck shows 23+mpg@65mph right after oil and fuel filter change. Make sure you change that filter every time you change the oil, and if you're using Amsoil or the like change the fuel filter every 5000 or so.

 

I got rid of a 2wdr drw 98.5 that was getting 20+ empty the only mod's were the exhaust was gutted ad it had a K&N filter only

to get a 4drw 4dr drw that is getting 15 down hill with tail wind on a trailer!

 

Fix what you have if you think you are getting lousy mileage now, just try a 6.7. I am lucky to get 15-17 on the highway with mine, and it drops like a rock down to 5-9 in four wheel in the oil patches!

 

my question is do you tow with this truck at all
meaning have you loaded the thing up and made it work
otherwise you have never woke it up

my 06 dually pulling a 40' gooseneck gets 15 - 16 mpg empty
does go as low as 7 if im real heavy or the load is tall and pushes alot of wind

 

I'm with ya' on the empty with the 40' but even with a wind catchin' load of 300+ square bales of hay the worst I got was around 9-10(usually closer to 9)

 

My truck gets around 17.8MPG.... My speedo has not been fixed for my larger tires. I get much better mileage running my Comp than I do stock. Sounds like you might have a VP44 or Fuel Pump problem.... Get that fixed and keep your 5.9L.......

 

Want some bad mileage, try driving my wifes 05 Hemi Durango. 11 mpg! Im trading it in for an 06 Jetta TDI. Hello 45 mpg.