I am about 50 miles from hitting 10k on my max and from what I have read and heard- the mileage gets better right around this time. I guess its finally broken in or something and the computer knows it? not sure..

anyways, my next fill up I hope to see an improvement, not that I am complaining now, but lots of you after hitting 10k your city mileage went up to 17 or so. I'm right about 14 using Level 1 or 3 with low boost 1 on both.

I'm at 6300 miles now and get 17-18 mpg @ hiway speeds 60-75mph. Got some lousy fuel in Seattle and drove to Cheney, WA (400 mi) and got 15 mpg. Fuel quality makes a big difference in mileage for me. I also use power service additive. These are DIC mileage, when I do it by hand it has been fairly close. Just the EGR mod.

Good luck. I am at 11,000 and still no improvement. About 15 mpg around the local rural roads. 11.5-12 mpg towing my 14' gooseneck horse trailer. 10.5 towing my 25.5' 5'er down the hwy @ 70 mph -:t . Still gotta love the truck. My '99 6.0 got about 7.5 mpg pulling the 5'er.

I don't think you will see it change like a light switch at exactly 10,000 miles.

no, I'm not expecting a drastic change, but most have voiced that around 10k, plus or minus it seems to get better. We'll see..I am curious.

15 is about the best I have gotten in the city and like I said I'm not complaining. Just like someone else mentioned above.. my 6.0 HD never got above 10.

i have 12500 on mine and get about 13 in town or highway. get about 7 to 8 pulling 15000lb fifth wheel. i saw no difference in my so far.

its funny how there isn't really a consistant mileage across the board with the LLY.. very strange

its funny how there isn't really a consistant mileage across the board with the LLY.. very strange
I agree with you briano..I just went over 10K a month ago..
20.5 MPG last tank...but, I have a feeling the handshaker helps a ton in this department.

Well, my last tank registered 16.7 and i have about 5500 miles on my truck. This is up from a low of 14.8 and an early average of mid 15s. I usually run hypertech stage 2 and i just turned it up to lvl 3 this weekend to play, so we'll see how fuel mileage changes.

I've hit the "magical mile" marker on a few diesels now. Seems like a great myth to beleive in, but I'm quite sure that if Mythbusters on TV got a hold of it....it would be dead quickly.

It will improve gradually. With 24000 miles, I hand calculated 18.95 mpg.

I think it all depends on your maintenance, the quality of fuel and how you drive...I can get 21 mpg going back and forth to work if I keep it around 60 mph, and drive like an old Grandma, but when I put my foot into it I will only get around 15 mpg, oh well still a little improvement of the 12 mpg I was getting with my gas truck, but oh how it pulls.;)

I now have 9800 miles and just today I got 19.3 hand calc'd (18.3 on the DIC) with the Juice on lvl 3 driving to the other side of the state. I set the cruise at 70 for the interstate, and there was about 60 miles of 55mph with a few stoplights. I am happy with that :) and I used to think I would never see above 15. If it keeps going up it's all a bonus :ro) .

On past trips, I really notice it go downhill above 70.

While pulling my 5er (about 10k / 12,500 GVWR) I got 13! Compared to my 6.0 gasser at 6 to 9 pulling and 12 -14 empty, I will not complain anymore :cool: .

I have 18,000 miles now and the mileage has pretty much remained consistant since about 5,000 miles. The truck got its best mileage between new and 5,000 miles. Go figure...

I am about 50 miles from hitting 10k on my max and from what I have read and heard- the mileage gets better right around this time. I guess its finally broken in or something and the computer knows it? not sure..

anyways, my next fill up I hope to see an improvement, not that I am complaining now, but lots of you after hitting 10k your city mileage went up to 17 or so. I'm right about 14 using Level 1 or 3 with low boost 1 on both.
Sorry to bring you bad news, but there is NO magical number where the mileage goes up. These trucks take anywhere from ABOUT 3,000 miles, to as much as ABOUT 20,000 miles to breakin.

My mileage went up each of the first 17 fill ups, (6,568 total miles) then stayed there. Others didn't see much improvement until 15,000 or more miles, then the fuel mileage would go up 2-3 mpg.

These vehicles are not intended for city driving. That`s what they built the Yugo for :eek: I have never drove much in town, so I don't have any info on city mileage, however; My unloaded mileage went from 16.8 on the very first fill up to 19.6 on the 17th fillup. There were a few ups and downs in there, but for the most part mileage went up. I have seen a low of 11.6 towing 10,000# to a high of 22.3, with an average of 19.7 empty, and 12.8 towing. It is possible that some towing had higher or lower mileage, but the fillup was mixed driving.

From everything I have read, these trucks have no set mileage, some can never get 14, while others never see less then 20. I can't say if it is manufacturing, or caculating, but I do know that I have kept a record of every bit of diesel I have used, and to date (At last fillup!) my truck has 68,248 with 3717.221 gallons from 164 fillups. (Average fillup is 22.67 gallon in a 26 gallon tank!) That`s 18.36 mpg with about 6% of the miles towing/hauling

15.9 mpg on dic 5000mi not reset from day one. Hand calculations agree. The truck is driven mostly on secondary roads with short highway use mixed in. Usually empty or lightly loaded at this point.

Dang, wish the 10K mile marker could be real. 8,100 mi. and the DIC shows 14.6, hand calc at 13.5 mpg. Not sure why it's off by that much considering modern technological advances in this computer age.
Still beats the heck out of the 12 mpg (on a real good day) with the old Landcruiser wagon - but at least now - I HAVE POWER! ! !

I still can't believe the 18.5-20 MPG soem claim... I am lucky to get 13.5 driveing around town liek grandma on Level 3 x 1.....

I am at almsot 17,000 mi. , run AMSOIL fluids throughout, change at half-the intervals and takin it easy for the last 5,000 since Tranny limped in a Level 5 highway run!!!!

I wish I saw the numbers ya'll have....

my average over 5 tanks is usually 12-13 MPG!!!

WILL:(

Briano ... I'm betting with Max Power, no noticable improvement when hitting 10,001. I'm at 13K and everything is the same.

As far as the variation of LLY milage figures, I think it is because we are comparing apples to oranges. Some trucks are lifted, some have different tire sizes, driving conditions are different, some folks use the DIC, or even the fuel gauge for reporting their milage figures. Most of the postings have not been "JJ" mpg certified, so they do not contain enough details to reach any conclusions.

Let us know what happens at 10K + 1.

I still can't believe the 18.5-20 MPG soem claim... I am lucky to get 13.5 driveing around town liek grandma on Level 3 x 1.....This is your problem!

I am at almsot 17,000 mi. , run AMSOIL fluids throughout, change at half-the intervals and takin it easy for the last 5,000 since Tranny limped in a Level 5 highway run!!!!

I wish I saw the numbers ya'll have....

my average over 5 tanks is usually 12-13 MPG!!!

WILL:(
Highway miles would/should be 3-6 mpg better then city driving.

10,000 miles sounds like an aweful lot to "break in" an engine. The main component in breaking in any engine is the rings, that happens way early on. Springs lose a small amount of pressure gradually so you gain in the frictional loss department slightly... maybe timing chains loosen up.....seals might not be super tight.....what is it that everyone thinks is "breaking in" in the engine???

In racing the engine is broken in after the rings seat, we got that done in an hour maybe two of operation by varying the RPM, and you could hear the exhaust change sound (deeper and deeper) as compression came up to where it should be.

10,000 miles is a massive amount of revolutions for the engine, even figureing low rpm usage, if it isn't well broken in by then it never will be IMO.

I am with the other guy, my mileage hasn't changed since the first couple k and it has about 14,000 now.

Highway miles would/should be 3-6 mpg better then city driving.

Thats why I hate the INTERNET everyone takes everything literally...

I actuall took "JJ's" and took a long trip just for mileage comparison... 210 mi. one way... Filled up tot he brim before leaving, drove the trip at Level 3x1 and reccoreded mileage... Re-filled to same spot and returned trip same speeds...

An amazing 12.8 there and 13.0 even going back!!!! I average 12.5 MPG with 60% City/40% highway... And ahve since about 1,000 mi.

I have actually GIVEN UP trying to improve mileage!!!! All the guys gettign 20 MPG must be on the highway 95% of the time and only in town long enough to back in and out of the Driveway!!!!

BIG

I never saw it. I've always gotten 20mpg when I'm nice and 17mpg when I hammer it a lot. These are all hand calculated since I can't believe anything the DIC says about mileage with power adders.

I'm not expecting any miracles or for it to one day get great mileage. I'm just going off of what I have read on here and most say around 10k the mileage got better. I hope its true, but as I mentioned before I am not complaining with the mileage I get now. I'd be exstatic if it was 17 in the city though!!!

A key factor in highway mileage is average speed. Down here the speed limit is 70MPH, which normally makes average speed 75MPH. Drop down to 65MPH (limit in other states) and mileage goes up. The other key factor is to define what city is. To me city is just that. Dallas is a city a small town out in the country, while not highway may be considered city to others. Mileage in these two different towns will be different.

The terms city and highway are terrible.

I don't tow very often and when I do it isn't super heavy. If I could have gotten 3.42's or even 3.08's when I bought my truck then I would have. The tow rating would be a little less but I am sure it would still tow what I wanna tow easily and would get way better mileage the rest of the time. Also would up top speed!

If they come with a 6 speed alli that has a deeper overdrive in '06 then my truck will be traded in right away.

Would be nice to be able to get a deeper overdrive AND a 3.42 directly from the factory!

Then your 17 in town would be easier and over 20 no problem on the open road.

I have a '05 with 2000 miles on it and shes getting around 15/15.2 This is doing the math. DIC says 15.7. I also have 285's and haven't recalibrated the Computer.

I hope she goes up in time. With the stock 245's I was getting 16.5+

I have actually GIVEN UP trying to improve mileage!!!! All the guys gettign 20 MPG must be on the highway 95% of the time and only in town long enough to back in and out of the Driveway!!!!

BIG
All the times that I get 19+ mpg consist of 90% highway/interstate driving. My truck get the best mileage when I keep the rpm at or below 1700. With 33" tires that is about 60-63 miles per hour max.

How much difference is the light weight of the various body styles. Regular, extended, crew cab, 6 or 8 ft. bed. My regular cab 8' bed has a light weight of 6008 lbs. This is another variable of endless variables to add to the mix in the fuel mileage equation.

I normally fuel from my bulk tank which doesn't have a meter, so I don't figure mileage that often.

However, I got 17.5 on a recent trip of about 560 miles. This was cruising at 75 mph, basically unloaded--just a toolbox full of crap. Predator was set to kill (mosquito eliminator mode).

I'm seeing slightly better mileage using a tuner and a few more miles on the clock, but it's not anything drastic at all. I'm at 19,500 miles now and have had the truck for exactly 9 months.

33K on the LLY now. Best I have goten is 19.5 at 70mph. RPM and fuel quality are a major factor in this motor. I went down to central Alabama Tues, 600 miles running 80 mph and got 17mpg. Coming back yesterday on the same roads till running 80mph with different fuel and got 18.5mpg.

Towing I have no idea because I have not towed anything far enough to check. But the end of the month will be going to Colo. pulling my 5th wheel and I plan to keep the rpm around 2K and I expect at least 10-12mpg. Guess we'll see.

Greg

I have a '05 with 2000 miles on it and shes getting around 15/15.2 This is doing the math. DIC says 15.7. I also have 285's and haven't recalibrated the Computer.

I hope she goes up in time. With the stock 245's I was getting 16.5+



Without recalibrationg for the larger tires then you are travelling further than the clock shows, if you haven't taken that into account then your mileage is higher than you think (more actual miles for the fuel used)

I also have 285's but re-callibrated the computer and checked it versus a stopwatch against mile markers at 60mph.

You might still be getting the 16.5+ (or even better!) and not realize it.


.

10,000 miles sounds like an aweful lot to "break in" an engine. The main component in breaking in any engine is the rings, that happens way early on. Springs lose a small amount of pressure gradually so you gain in the frictional loss department slightly... maybe timing chains loosen up.....seals might not be super tight.....what is it that everyone thinks is "breaking in" in the engine???

In racing the engine is broken in after the rings seat, we got that done in an hour maybe two of operation by varying the RPM, and you could hear the exhaust change sound (deeper and deeper) as compression came up to where it should be.

10,000 miles is a massive amount of revolutions for the engine, even figureing low rpm usage, if it isn't well broken in by then it never will be IMO.

I am with the other guy, my mileage hasn't changed since the first couple k and it has about 14,000 now.

Don't mean to bring a thread up from the dead, but this 10k miracle MAP change made me do a search. I agree with TxC, if an engine is not 'broken in' within a couple hundred miles, it will never be. Read this and see if you don't agree.

http://www.mototuneusa.com/break_in_secrets.htm

Unfortunately, I read this several months after I got my '05. I have a feeling that it will never run as well as it could have...