My mileage is normally ~16 all around hwy & some city. Yesterday @ 70mph on the interstate the overhead said 16.4. Overhead on my truck is usually close to hand calculated. Regardless. I want more. I have a new SO MWFI VP.Let's start with making sure we're up to spec then mod. What get out of adjustment or wears & reduces mileage? Will start by checking:adjusting valves, cleaning IAT & MAP sensors

Drop your speed to 65mph or even down to 60mph will yield you a HUGE increase in mileage. Go easy on the go pedal starting out........pretend there's a raw egg under it that you don't want to break. Air you tires up.........I run my 04.5 at 70psi at all 4 corners. Don't go crazy aggressive on tire tread............do you really need mud tires on that "urban assault vehicle" that leaves the black top 2-3 times a year???? Make sure your brakes aren't dragging and your bearings are sound. Have the front end aligned. I'll stop there, otherwise no one else will post here.With my 04.5, the year round average is 550-600+/- miles per tank..........sometimes as much as 3/4's of that is towing my work trailer. In the warm summer months, I average usually around 19mpg in combo driving around suburbia. Now that it's getting a bit cooler it's dropped to 18ish. In the winter, it'll be 14-16mpg in combo trailer towing/empty. I set a mileage and mpg record for my truck just over a month and a half ago.........................23+mpg and 727 miles on one tank of fuel. It was hotter than (insert colorful metaphor) but my truck is decidedly "warm blooded"!!!!You have to "drive" for mileage. On that 100 mile trip, are you really needing to drive 80mph to get there 15 minutes faster than if you drove 65mph???? It's a lifestyle thing. Sure, I can, and occasionally drive fast down the interstates. But for me, that's "stressful". I'd much rather set the cruise at 65mph and let all the assholes pass me. For me it works...........some folks can't/won't do it!!!

tires and speed are the 2 biggest things on a properly maintained trucki have no chip or programmer. only what is listed in sig. and i was getting 19.6-22 with 33x12.5r16.5 on the rear. when i changed out all 4 corners for yokohama geolander ats 245x75r16(factory size) my milage dropped to 16.4-19.4i get these number running empty(but have a full ladder rack) with mostly highway at 55-60 mph

Alright I had to go to town to top off and let you all see what I get. The numbers are 8.807 Gallons for 181.9 miles. That equates to 20.654 mpg. You guys think that is good? Well let me throw in that 1/4 was city driving, 1/4 was me beating the absolute crap out of it (for fuel pressure testing purposes). So how do I get it? Well the last 1/2 was driving to the city on a 55mph highway. I do 55mph the whole way, feathering it up hills and letting it coast up to 60 down them. I rarely get over 65, even on the 4 lane I drive 60. In the city, don't slam on the brakes, just let it coast to the light. When it turns green, don't floor it, take it easy. Do the things Dorkweed and Guesswho said too. One rule Mike used to say was "keep it under 5psi and 600F EGT and you will see 20mpg" and this rule really is the best way to ensure that you do get 20+. Alright now I told Mike a while back I had never seen under 21mpg unloaded and this is no exception. I changed the fuel filter and cleaned out the prefilter and that probably totaled a quart according to the gas can I put it in, I also had to tap the banjo bolt for the injection pump for my fuel pressure gauge which drained the injection pump, that was probably another half quart but I will ignore that fuel for **** and grins. I dumped all that fuel into the tractor, not back into my truck. I went to the exact same pump also.. So 8.807-0.25 (the quart) means I actually only burned off 8.557 gallons. Which equates to 21.257 mpg. So my 21mpg record still stands.

Biggest killer is speed... Just going from 55 to 65 MPH will produce double the load. So first off slow way down and set your cruise at 55-60 MPH if you can safely. Dragging brake shoes and/or pads. A single caliber with a gummy puck will eat over 3-4 MPG off your typical MPG number. Don't let this bite you and buy new calipers or brake parts most of the the time you can clean the parts and reassemble and gain back your MPG number.

I can drive nice (when I'm feeling cheap). I've never seen consistently above 16 but think that's low even with 410 gears. 20 would be outstanding. The savings might even pay for some more toys. Brakes aren't dragging - rears probably need to be adjusted tighter since I've ignored them for a while.What are the maintenance & adjustment items?

I can drive nice (when I'm feeling cheap). I've never seen consistently above 16 but think that's low even with 410 gears. 20 would be outstanding. The savings might even pay for some more toys. Brakes aren't dragging - rears probably need to be adjusted tighter since I've ignored them for a while.

What are the maintenance & adjustment items?

Even with 4.10's you should be able to pull off 20. Not at 70mph, but at 55 you should be able to no problem.

Wear parts and adjustment things that can decline mileage are things like

[*]Air Filter

[*]Fuel Filter

[*]Clogged Exhaust

[*]Front end alignment

[*]Dirty Injectors

There are other issues pertaining to the drivelin, have you jacked it up and spun the wheels and driveshafts to see how good they turn?

I'm running stock except exhaust with 4:10 gears. I usually run in the 18's running empty... rarely into low 19's. I don't believe in flooring it but I HATE people who make others jack up (wrecking the other's mpgs) so they can pull into traffic without using their throttle for the purpose God intended it for. My overhead is right on, every time I've checked it... but understand it would not be with a modded truck. I think the stock ratio is much better for mpgs. 4:10 is too low for highway speeds with stock tire sizes. Russ

Even with 4.10's you should be able to pull off 20. Not at 70mph, but at 55 you should be able to no problem.

Wear parts and adjustment things that can decline mileage are things like

[*]Air Filter

[*]Fuel Filter

[*]Clogged Exhaust

[*]Front end alignment

[*]Dirty Injectors

There are other issues pertaining to the drivelin, have you jacked it up and spun the wheels and driveshafts to see how good they turn?

The only time I see 20 on the over head is after a reset when it's cycling down to 16.

Air Filter is stock but clean.

Fuel filter(s) on the AirDog are new within 1000 mi.

I have a lifetime Firestone alignment. Toe is 0, caster about 3*.

Haven't had the wheels off the ground for a while. Will check those & spin drive shafts when I have tires balanced.

Can't speak to injectors. PO replaced entire exhaust before I bought it ~ 40,000 mi ago.

Anything else on the engine?

ohh i forgot to mention that i took my muffler and resonator off and picked up 1-2 MPG. that was how i stopped getting lower than 15 empty(back b4 the humvee rims)

This applies to the VP44 trucks. I know as the boost pressure rises the timng curve start to retard some. So if you boost rises above 5 PSI you losing timing now. Also more boost means more fuel used. As for the pyrometer more fuel means more heat so keep the heat down and MPG's will naturally rise up. Now how I found this tidbit was playing with a smoke switch and you can phyiscally hear the rattle change or disappear as the boost fooler is switch on (full boost). Then return to normal (0 boost) and rattle returns. Nice part is most of Idaho (in my local area) the highways are in the range of 45-65 MPH. All city streets are 25 MPH. Then all residential areas are typically 15 MPH. Most of the time I set the cruise for 55 MPH and most of the time traffic doesn't mine and they just tag along.

I just replaced my VP44 injection pump and mileage went from 17.7 to 19.7 for a 2 mpg increase. My injection pump had the P0216 code which means the timing piston was binding up and full advance could not be achieved. I would check the codes since the MIL light does not show when there is a P0216 code. I am also thinking of the Diablo Puck D7153 for the 2000 year I have. Apparently it adds 50 hp which is probably the limit for a stock auto but it advances timing and most claim a couple of mpg increase. Timing has a lot to do with the decrease in mpg since the 1st Gens. Most owners will remember when the ISB first came out in 98.5 Cummins had the ECM programmed so the timing (and mileage) would go up as the odometer went up. This was so it would pass the initial federal emission (EPA) tests. Navistar, Cummins and Detroit Diesel were fined over one billion dollars on this. Owners were puting padlocks on their ODBII connector so Dodge dealers could not retro-load the retarded timing software when in the dealer for service. The retarded timing and DPF's in 2007.5 is the reason most 2010 Dodges get about 30% worse mileage than us. It is not because of a heavier vehicle or more horsepower as the manufacturers would like us to believe. I have the court documents and press release in Adobe format if Michael wants it in the download section. It was picked up off the EPA site.

I just replaced my VP44 injection pump and mileage went from 17.7 to 19.7 for a 2 mpg increase. My injection pump had the P0216 code which means the timing piston was binding up and full advance could not be achieved. I would check the codes since the MIL light does not show when there is a P0216 code.

the Check Engine Light doesn't come on when you have a P0216? i thought that the CEL was suppose to kick on if you had any detectable effect on emissions.

Most owners will remember when the ISB first came out in 98.5 Cummins had the ECM programmed so the timing (and mileage) would go up as the odometer went up. This was so it would pass the initial federal emission (EPA) tests. Navistar, Cummins and Detroit Diesel were fined over one billion dollars on this. Owners were puting padlocks on their ODBII connector so Dodge dealers could not retro-load the retarded timing software when in the dealer for service. The retarded timing and DPF's in 2007.5 is the reason most 2010 Dodges get about 30% worse mileage than us. It is not because of a heavier vehicle or more horsepower as the manufacturers would like us to believe. I have the court documents and press release in Adobe format if Michael wants it in the download section. It was picked up off the EPA site.

i didn't buy this truck until 07. i don't know if my VP44 or software is original, and have thought about see if there was new software. perhaps i should not get an update? does the SMARTY programmers stock setting set the timing to the "retarded" software? i would love to see that pdf file!

the Check Engine Light doesn't come on when you have a P0216? i thought that the CEL was suppose to kick on if you had any detectable effect on emissions.

Mine did not come on in a 2000 but I imagine the rules were updated afterwards.

i didn't buy this truck until 07. i don't know if my VP44 or software is original, and have thought about see if there was new software. perhaps i should not get an update? does the SMARTY programmers stock setting set the timing to the "retarded" software? i would love to see that pdf file!

By law they were supposed to put an update sticker on the ECM located behind the fuel filter with the date and the software Release number. A flashlight and mirror should be good to see it. The defeat software only lasted about 6 months (production starting July 1, 1998) before the EPA caught on. I have both the final announcement on the one billion dollar settlement plus the "Consent Order" to Cummins outlining the settlement for complete access to the manufacturing/engineering design/testing facilities(unsigned version). I will download it but Michael looks them over before they appear. I will submit to Other Manuals and Documents.

Yea I got to authorize the files for download use... So let me know when you do upload to the site because it doesn't notify me...:banghead:

Downloads have been submitted but here was the Recall 8001 notice: http://dodgeram.info/tsb/recalls/8001.htm Of course there is no mention of the EPA lawsuit on "defeat devices" in the recall but you can be sure that it did happen! The recall was because the ECM software advanced timing as engine hours passed threshold values. Everyone used to exclaim in the forums: "Put some miles on that new truck and your mileage will go up 3 MPG!" The VP44 was the first pump that could dynamically control timing with RPM and load but full advantage of the engine efficiency could not be achieved legally. Prior to the ISB the timing stayed constant through the RPM range which was a huge disadvantage at high RPM (2000+ RPM) were injection combustion delay was significant.

I seem to have lost significant mileage since I put on my Airdog and Toyo Open Country M/T's 285/75/16. I can't see the pump doing anything so would the more aggresive, slightly over-sized tires do it? I can't say exactly how much it's dropped but I'd say between 2 and 4 mpg's. The truck had 265's on before I went to the 285's.

Rotational Mass & Rotational Resistance got you...

Cooper STT's 265/75 R16 (16-18 MPG) vs. Big O AT's 235/85 R16 (19-21 MPG)

Face width of the Cooper STT and tread design

Weight of a Cooper STT 265/75 R16 tire

Big O AT 235/85 R16 width and tread pattern

Big O AT tire weight