New owner here with a 2003 2500 QC/LB SLT 4x4, auto trans. This is my first tank and so far the trip computer is showing low 16's for mpg (did reset during fillup). I'll try to get a fairly accurate measurement when I fill up next, but with the foaming/filling issue, I can't be 100% certain it will be exactly the same fill up point each time.

The truck has 7300 miles on it currently.

Does this fuel milage sound in the ballpark? All driving since I've had it is around town with little or no prolonged highway runs.

I just bought some Rotella DFA to use on fill ups. I'm hoping that with more experience driving the truck and also the fuel conditioner that I can somehow get the milage in the 18 range around town. I now I'm splitting hairs here, but I'd like to see how high I can get it to go just for personaly satisfaction. Heck, anythings better than the 8 mpg my '89 Suburban 454/th400 was getting .

Any simple tricks folks here have found that helps improve milage? Looking for non-modification type stuff.

 

First weekend in mine, put about 260 miles on it, mostly 70 mph highway miles, with about a third stop and go stuff. The trip computer showed between 19 and 22 highway and 15-16 stop and go. Filled up and did calculation came up to 16.9.
My other 2 fillups with the truck, I'm still learning how to "fill it up" with out burping diesel foam.

Doug

 

I posted some info on my '03 a few days ago.

Might be helpful. Go to the front of the thread.

https://www.dieseltruckresource.com/...163#post391163

 

Your mileage sounds about right for a NEW truck. Wait until you get it broken in. as far as the foaming you will get 1000's of ways to fix it or atleast make sure you get the same fill every time. All I do is fill it until it stops and then maybe spend another five minutes topping it off. It's close enough if yo do the same thing every time.
I get about 12mpg's around town (less than 45mph with lots of lights) & any where from 18 - 23 on the highway if I keep it down around 1800 -1900 rpm's with the cruise running the truck.
I do have 23k mile on the truck now and I'm running complete synthetics thruout (AMSOIL)

 

The best trick I'm aware of is to keep her under 1900 rpm on the highway - hard to do around here without getting rundown constantly.

 

Rather than doing a tank-by-tank calculation of fuel mileage, keep track of fuel and mileage over a few tanks. That'll eliminate the problem of not filling it up to the exact same level at a particular fuel stop. And don't trust the computer to be accurate.

I plotted my fuel mileage for the first year and a half. Tank-to-tank mileage varied (probably mostly from not filling it up exactly the same each time) but the running average was pretty constant for the same driving habits (lower in town and towing and higher when empty on the highway). Last time I checked I was averaging around 18.5. It increased about 1mpg from new until I quit checking.

 

I think the key to mileage is in the gearing of the truck, and what rpm range do you normally operate at. Keep it under 2000 rpm, and it makes a substantial difference. My truck has 4:10's, and its about 62 mph that I'm at 2000 rpm. (If I remember right) My "old" truck, a 2001 2500 eth/dee, had 3.55's and 2000 rpm I was in the low 70's mph. Great for milage, and highway cruising, but not as good for towing heavy. (stock) (I know with mods its fine)

Cat Cracker.

 

just posted @ the 600 survey 04 555 4x4 6speed SB 3.73s stock 265hiway tread each check over 400 mi 1st tank 17.75 2nd 19.75 3rd 19.2 4th 21.47 mixed driving first three tanks including short trips 2 days stopngo in traffic ,showing off to ford owner friends couple 100mph runs last tank included 410 mi on I,5 45min of stopngo the rest mostly 65-70 half the time raining like a bas#@^% I am super STOKED !!!

 

Checked my computer this weekend and running average of the last four tanks is 18.5

This is mixed driving with Interstate,Secondary and In-town driving.

I now have 5K on the truck

 

Just went through the first official tank of fuel here since purchasing the truck used.

The trip computer was showing low 16's most of the time with 15.9 showing at fill up this afternoon. The odometer had 428.1 miles and the tank took 29.0 gallons of fuel...felt as though it should have been pretty close to fuel as it was when I filled it previously. That calculates out to 14.76 mpg. I'm somewhat disappointed with that number, but know it'll take some time getting used to driving the truck as my previous vehicle was a 454 gas Suburban 4x2 which got in the 8 mpg range.

I sure would feel a whole lot better if I could get the around town milage in the mid 17 raneg consistantly. This first full tank was all around town, no highway driving.

This next fillup I added approx 10 oz's of Rotella DFA fuel additive. Hopefully that in addition to more careful right foot control will help improve the fuel milage.