I'm into the 3rd week of owning my new truck and I can not believe the difference in fuel economy from my 03 Hemi. I even hesitate to tell people the mileage my new truck is giving me but doing the same thing every day the old truck would give 14 mpg and the new one is at 22.5 and I'm guessing it will get better, I'm only at 2000 miles. Calculations have been done with pen but seem to resemble what the computer is showing. Oh yeah the truck is a 04 555 6 speed 4x4 quad.

 

Everyone getting 20+ mpg must have a perminate tail wind and light foot. I have never averaged better than 16-17 on a 500 mile or greater window.

 

Some trucks just get better mileage than others. Best I've ever gotten was 25 out of my 01 4x4. I usually average about 16-17.

 

27,000 miles, and never better than 17 I`m not buying it

 

Whew glad someone else is getting the same mileage I get. Actually since yours is a 4x4 you are getting better than my 2wd. You 17 to 18 mpg guys must have a heavy foot.

 

Oh, I believe it... my buddy with a 555 gets that kind of mileage all day long. However, the only time MINE has gotten that type of mileage is when it was sitting on top of a moving railcar!!

 

I know break-in, etc. has a lot to do with it, but I've also heard that the timing of your engine (From factory) will have a lot to do with it.My brother's '03 SO with 3.73's makes up to 25mpg. When it idles (at 15000mi) it makes sort of a popping sound that he doesn't like (popcorn maker?). But it runs great, and the mileage is awesome! Mechanic(good mechanic) told him that any of the units he has run into that "pop" seem to be getting good mileage. Timing??

 

I drive 110 mi a day , work commute, and average 21 mpg with pencil. Best tank on road trip , empty truck, was 23.7 , with pencil. I have noticed when I run I-44 to work at 75-80, mpg will drop a couple mpg.
Same with towing at 70 mph ,12000 lb 5er it gets 11-11.5 mpg. Towing at 55-60 mph it gets 13-13.5 mpg.
RPM isa big factor in fuel milage.......JIM

 

You know, I have the same thing. Been told by friends with HOs that my truck just sounds funny. I would describe it as a fast chop..chop..chop, like a 350 with a hot cam in it. Since switching back to summer fuel, I went from 13 city to 16/17, 19 highway to 24. Overhead is always within 1mpg when checked by pencil with the TST box off. Did 400 miles the other day with cc set at 70 and my overhead climbed to 26 on flat stretches. No TST. Honest! I'll take a picture of it.

 

I am happy for you guys that are getting the good mileage. I had a chance to by a 555 but just had to get the 600. The best highway mileage I have gotten in 3500 miles is mid 16s hand calculated. The overhead shows around 10 in town. I am about to make a 600 mile trip pulling 8K+ so maybe that will help. If I can even approach a highway average of 20 I will shout for joy!

 

WELL, at least some of you guys have the luck! I drive like granny and best so far is 14.5 in city. At highway speeds of 70 + it goes down from there. Truck runs great as far as acceleration and no missing. I do get the pinging sound at low accel but i am afraid to take it to dealer. I called a salesmen/truck onwer who works there adn has a 2004.5 and he says that anyone claiming over 14+ mpg. is "jsut not getting it". But, i believe you guys cause there is no reason to lie. I may try convincing the dealer that i need the TSB 20325251AFXOG as mentioned in another thread. If this TSB has worked for anyone and resulted in better MPG, plz say so here as i will check back.

2004.5 QC 2500 4X4 SLT Everything but leather.

 

BiggRigg600, let me know if you get the dealer to use that TSB# that has been thrown around. The TSB20325251AFXOAG number that Jeremy gave out on another thread. I am leery of my dealer here in Tucson, so if you get your dealer to do the flash and you get good results, let me know and i will pressure my dealer to do the same. Otherwise I am still pushing around at 14mpg. Hmmmm.

2004.5 QC 4X4 SLT 2500 everything but leather.

 

Don't know if mine has the poor mileage as I have gotten 16.4 and 16.89 combined city/highway driving in the 2 fillups. I only have about 800 miles on the truck and after the Ford 460 I am very happy. From others I have read that it should start improving after several thousand miles. This truck is currently my daily driver and my speeds have ranged from under 25 to about 70 or a little better.

 

In 15K with a Diesel Dynamics True Torque box, installed since 2K in position 3, I am averaging 18.5 + a smidge, hand calculated with a 3.73 LS diff. I have a Jason cab height topper, installed 4 Craftsman bed mount truck tool boxes (full), and a Toff spray-in bed liner, all toll maybe 1000 lbs over factory weight. About 65% of my driving is 70+ mpg. Not many mountains in South Texas but have made a trip to LA via I-10 and I tow a heavy fibefglass boat to the Gulf Coast 52 miles away from home about 5% of the time.

All and all much better than my 89 Ford 4 X 4, 5.8 liter, five speed with 3.55 diff.

Of course I get really terribly mileage on my bicycle, 6 pack / 15 miles. Cost per gallon very high and it doesn't tow very well.


L8r,....................dogger

Days on, sweatin' in the Sahara Desert!!!!!!!!!!!!!!!!!!

 

Hey There,

A few things people are forgetting. Bigger tires impact milage GREATLY. The four-speed auto compared to the six-speed manual transmission, will give you much poorer fuel milage, because you only have four gears to play with and not six, cannot control when to shift, and rev at much higher RPM's with the auto. I have driven a thirty-five hundred SRW QC, LB, 4X4, and get twenty-one EASILY at seventy, reving at nineteen-hundred RPM's because I have the six speed. I also have the stock tires, and Leer canopy, along with MBRP dual exhaust and AFE Pro-Guard Seven replaacement air filter. Just a few things to keep in mind, when comparing milage. Read peoples' signitures carefully, to know what kind of truck they have, and the mods on the truck, and think about which mods will help milage, [canopy, exhaust, air filter, ETC] and which mods will HINDER or DESTROY milage! [LIFTS, bigger tires, big front ends, bumpers, loads, tool boxes, ETC] Just my two cents worth.

James