I met BADBOWTIE yesterday and he is knows a lot about Diesels, we agreed on one point, Flying J is the best place to get fuel, better product and better mileage, I run it all the time and so does he.
At 60 with 3.73's with the 315's I get 22 plus with only 1800 miles.

Dude, do a cruise control run at 60mph and see what you get, I bet you are close to me, at 65 I get 20.5ish.

I think your rig is getting excellent mileage.

 

I have the same truck and AFE but I also have a ARE topper. I am getting the same milage. The truck also seems to be running better as it gets miles on it. I really noticed a difference around 3K, it now has 5K on it and it just keeps getting better. Jim

 

I Drove 3500 miles last week between meetings in the Polar nether world of Northern Ontario, It was -40 windchill most of the week with too much snow so I was in 4x4 even on the divided highway sections, winter fuel, and even at one French service station a gallon of unleaded (lost in translation), lots of idle warm up time, and hours of around town driving and parking... over the trip I got 17.8 mpg computer and 17.9 calculated. Great for a frozen Dualie.

On my way up the divided highway was closed for plowing so I 4 wheeled it threw some drifts to the entrance and when it opened I passed the purolator van and had 1.5 hours of no traffic at 80mph (mpg dropped to 17.4) worth it

 

My 03 HO,3.73,6 spd is getting 21-23 mpg. All my driving is hi-way, 110 mi work commute, which on 2 lane at 55-65 gets the best. If i take turnpike to work,75-80 mph, mpg drops a couple. Sorry but just don't have a town to drive around in......JIM

 

so if i had a crew cab short bed with 3.73 4x4 .....what can i expect on the highway and what in town? I have a psd 7.3 and i get 18.3 at 69mph. IT is a crew cab short bed 4x4 with the 6spd.

 

I get about 15.5mpg average...Im towing at least one time with each take also... And I drive it very hard...All stock except for straight exhaust...

 

My truck currently has 9000 miles on it.
Around town with 1/2 highway & 1/2 city streets I average 17 MPG, the best I've seen on the highway is 23 MPG, towing my enclosed trailer (about 5500 lbs) 11.5 MPG.


All those MPG figures are better than I got with my 318 Dakota.

 

Some excellent responses here, thanks!

So what do you guys feel is the 'break-in' (or is that broken-in) mile marker at which you'll see the best MPG with no more increases?

 

With about 15,000 miles on it and alot more hours than most with alot of snowplowing I would consider mine "broken in". I'm gettin 20mpg almost all of the time now. Except when running over 75mph!

 

Drove from Ft Hood to San Antonio yesterdy...With Brushguard, wheel liners, fender flares, mudflaps, nerfbars, 31570r17 tires...getting 19.9 - 20.5mpg at 70mph with cruise on. Worked numbers manually with calculator and miles traveled on odometer to gallons to fill and it came to 20.4 mpg.

 

3.73 rump w/ anti-spin- if temp is less than 15 mileage is 15 in town and 20 hwy-- if it's warmer then about 19 in town and 22-24 hwy- hi-speed (over 70) gets about 22 flat out-- mpg has gone up with mileAGE as expected-- no DFA even at -20 F

 

ABC, your numbers are incredible! Hang on to that one! 6 wheelin', pushin' snow,runnin' going nowhere with freeze fuel in her belly and a French tickler **** tail additive for good measure, WOW! If you tell us it's an automatic I'm gonna make you an offer!

I Shopped for a ctd with 3:55 or 3:54 4x4 rears for over the road trippin'. Got an 01 a year ago, put a tranny and TC in it and a 10 ft. slide in on it and headed 80 west. Hills of Pa.-13mpg,ohio/Illinoi flatland-14.5, Nebraska w/headwind couldn't get 10.5 or run in over drive,Colorado/Wy/Utah-11-12, Arizona/New Mexico-12.5. Texas to Fla.-14 and 12.5 following the atlantic north to PA.
Unloaded in N.E.Pa. I was gettin' 14-15mpg and wanted better. My non turbo 6.9 F350 C6 auto gave me steady 16mpg with 4:10's.
After breathing better via K&N in and 4 inch out I was seeing 15-17mpg.
Recently, I planned a 4 week run to Kansas/Oklahoma and about, so I lubed the ctd and both diffs with Amsoil and employed an edge comp at level 3 for some towing kick!
Latest figures, towing 6000lb TT, 70 miles into the trip , hilly up-hilly down highway cruisin' at 65mpg the on board read out was hangin at 17mpg, in OD, with power to spare, RIGHT BEFORE THE MOTOR PUKED !! I wounder how long I was rubbing the bearing the wrong way and what affect it may have had on engine efficency/power/mpg and if below the norm mpg could be indicative of problems to come?[later in a new topic thread]

B Dude555, My CTD is now getting excellent economy, IN fact its not burning any fuel at all sittin' in the shop waiting for the new short block !! Oh well, pay up , take my chances and enjoy it while it last! I think your mpg #s are just fine though if I didn't suffer from cronic LCL [lazy clutch leg] I'd be in a new ride, 2 wheel dr., 6 speeds forward, gear vender assisted, smoothed out and lowered, lookin' for 30 MPG cruisin' down the road! STY

can't afford the warranty stuff but still enjoying the extras !!

 

I am getting 19-21.5mpg on a mixed circut of (stop and go) highway and interstate driving consistantly.

Was a-scared when I first bought the truck a year ago and was only getting 17 to 18mpg.

After the engine sat in, around the 24000mi mark, it started to get better milage.

One of the biggest factors in getting better milage is to shift before you hit 2000rpm, keep the darn electronic throttle steady, and keep your top cruising speed below 70mph.

Even on the back roads in 5th I can muster an honest 20 mph if I keep the engine speed below the 2000rpm mark and keep the throttle steady.

 

Hey rednose don't fret, youer mileage is what I get and I know that most of these people that say they are getting great mileage around town are NOT really driving in town, ie not going more than 40-45 mph with lots of stop and go and lights and speeds really at about 25 30 most of the time.

I will say that when mine was new a did get 21 mpg during my first long run on the highway round trip form Portalnd to Seattle, but of cours e that was running around 65 most of the time.
When I did my first accross the country pull of my TT I averaged 11.5 mpg, of course that's running hard after the first 500 to 1000 miles.
Now I can get 19-23 mpg on the highway running empty at about 1900 rpm's (65-70) that's all stock except for the AMSOIL lubes.
I still get about 11.5 pulling my new 5VR thru the mountains out to the beach and back
Citty milage is now at about 12-14 steady if I stay out of it and stop racing people off the lline.

 

I have been reading the posts about m.p.g and the Cummins 600. Generally, most people seem to be reporting poor mileage with the 600.

I think I read somewhere that the reflash for cold weather hesitation will also improve mileage. Has anyone else heard anything like this?

Interesting Stuff!