7 MPG big issue what am I doing wrong?

[2003F350]

I'm still not sure how so many of you guys can't break 12mpg in your Wagons. I routinely pull off 14-15+, but then, I rarely go over 65mph. My drive to work is 30 miles of 55 mph or less, and even on the expressway I set the cruise at 70 and call it good - because my mileage drops to about 13.

Long story short, if you want more mileage in these things, slow down. You're driving a brick, it's going to get the mileage of a brick.

 

[olyelr]

I'm still not sure how so many of you guys can't break 12mpg in your Wagons. I routinely pull off 14-15+, but then, I rarely go over 65mph. My drive to work is 30 miles of 55 mph or less, and even on the expressway I set the cruise at 70 and call it good - because my mileage drops to about 13.

Long story short, if you want more mileage in these things, slow down. You're driving a brick, it's going to get the mileage of a brick.

I am a geek when it comes to getting good gas mileage. I know how to drive to get as good as mileage as I can. My power wagon is usually around 12-12.5 on average. Worse in the winter. Little better in summer when cruising long distances. Best I have ever seen with it was just below 14. They just suck gas, thats all.

 

[Grand Mesa]

The speed limits on the Interstate here are 75 MPH and in nearby Wyomong, Utah, and Nevada they are 80. I wouldn't feel safe poking along at 55 or 65 MPH.

Yes, driving 55 saves fuel.

 

[Trailmaker]

I can’t believe this thread is still going especially when it seem that the OP figured out that he didn’t adjust his odometer to his new tires and he is probably was getting closer to 10 or 11.

got to love the 8spd. I can claim 17 with the cruise set to 65 or drive 75 and claim 15

 

[olyelr]

I can’t believe this thread is still going especially when it seem that the OP figured out that he didn’t adjust his odometer to his new tires and he is probably was getting closer to 10 or 11.

got to love the 8spd. I can claim 17 with the cruise set to 65 or drive 75 and claim 15

View attachment 192614

im sooooooo jelly! I want the 8 speed so bad. But i refuse to trade up until they get the new cab on the hd’s.

 

[Mythanar]

Hmm. What are you guys doing to your trucks? Attached is my last road trip from Seattle to California (San Diego) and back. San Bernadines, Yosemite, Shasta mountains, death valley. All of that trip included, some miles over snow / offroad (in death valley).

3.6k miles in total. 14.5 mpg *average*. There been places it was somewhat under, somewhat over (15.3 best I saw), but averaged to 14.5 mpg overall. Truck was loaded with 2 adults, 2 kids and I imagine ~300lbs of gear.

 

[Grand Mesa]

I got 17.0 MPG on summer gas blend within an approximately 150 mile stretch driving my PW west bound from Vail Summit to Grand Junction on I-70 at the 50 to 75 MPH posted speed limits. It's a bit over a 6,000 feet drop in elevation with just a handfull of very short unnoticeable uphill stretches, otherwise its nearly entirely all downhill. Going the other direction its gas mileage sucks at just 13 MPG. My theory is that the PW gas mileage improves dramatically when driving it west. So go west young man.

 

[Trailmaker]

im sooooooo jelly! I want the 8 speed so bad. But i refuse to trade up until they get the new cab on the hd’s.

Lol here is a few more to wet your appetite. I was messing around with 55 mph for 50 miles and on the way home at 65mph just to show off good mpg on a bad mpg thread.
To be honest I normally get 11-13 cause I drive over 70

 

[olyelr]

Lol here is a few more to wet your appetite. I was messing around with 55 mph for 50 miles and on the way home at 65mph just to show off good mpg on a bad mpg thread.
To be honest I normally get 11-13 cause I drive over 70

View attachment 192621

View attachment 192622

Well if I reset my computer when I'm coasting down a mountain I can snag those kind of numbers too! LOL

 

[ALRedneck]

Last 15,000 miles on 87 octane. I’ve reset the trip to see what 15,000 on 89 octane will do. So far, I believe I’m at 2,500 on 89 octane with no difference. 89 is 0.30 cents more per gallon so it’s not looking good for me to stay with 89. That 15,000 is a mix of idealing with ac on, towing with it locked in 4th and 55 mph as DD. FYI- it would probably hand calculate to 13 mpg

 

[olyelr]

Last 15,000 miles on 87 octane. I’ve reset the trip to see what 15,000 on 89 octane will do. So far, I believe I’m at 2,500 on 89 octane with no difference. 89 is 0.30 cents more per gallon so it’s not looking good for me to stay with 89. That 15,000 is a mix of idealing with ac on, towing with it locked in 4th and 55 mph as DD. FYI- it would probably hand calculate to 13 mpg

View attachment 192656

True about the hand calculation.

Also, no matter the miles since last reset, the average mpg average is only for the last 500 miles (roughly).

 

[ALRedneck]

True about the hand calculation.

Also, no matter the miles since last reset, the average mpg average is only for the last 500 miles (roughly).

Didn’t know that!

 

[bigdodge]

Higher octane will do nothing for MPG.

Sent from my Pixel 4 XL using Tapatalk

 

[Bennyrok]

Hi! figured I'de share my stats with ya, I've been running 37x12.5x20's for a couple of years now this is a 2014 5.7L Bighorn extremley modded with a 4 inch superlift, also running a flowmaster set up w/ 5 inch exsaust tips, and a few extras and I still only get 9.0 to 9.5 miles to the gallon, I'm about to fix my tire ratio with the OBD in a few weeks I'm sure it will make a difference but I don't expect a big one. This is the price I expected to pay when I changed most of the truck. Good luck in your endeavours!
Tough lookin truck by the way!!

 

[ALRedneck]

Higher octane will do nothing for MPG.

Sent from my Pixel 4 XL using Tapatalk

Is that in all cars or just PW? Guessing it affects how well it runs but I honestly can’t tell the difference. Even the MDS seems the same.

 

[bigdodge]

Is that in all cars or just PW? Guessing it affects how well it runs but I honestly can’t tell the difference. Even the MDS seems the same.

Higher octane will resist higher heat before it detonates. Higher compression will create higher heat which in turn will donate fuel before the spark, that's spark knock or pre ignition. That's a very basic explanation and I'm sure someone will come along and argue it or expand on it.

Sent from my Pixel 4 XL using Tapatalk

 

[Trailmaker]

Is that in all cars or just PW? Guessing it affects how well it runs but I honestly can’t tell the difference. Even the MDS seems the same.

Higher octane will resist higher heat before it detonates. Higher compression will create higher heat which in turn will donate fuel before the spark, that's spark knock or pre ignition. That's a very basic explanation and I'm sure someone will come along and argue it or expand on it.

Sent from my Pixel 4 XL using Tapatalk

this is going to open a can of worms on a ridiculously long thread on miles per gallon on a power wagon already lol

but I will comment as I have on the heavy duty section. If you want the eco mode to work without vibration and to save you 2-3 mpg when engaged you will need mid grade as it is recommended in the manual. I took a 3k road trip and included mpg in my experience. I wrote a whole thread day by day of my trip into the smoky mountains. What I did not know was how my wife got 2-3 miles more per gallon then I did and was not till 2 weeks after I got home I realized that when I selected 8th gear ( so I could watch the down shifting patterns while in the mountains) it turned off mds. And when my wife drove she just put it in drive a let it alone. Since my trip ( in my 2019 with the 8spd) I tested it a few ways. And 89 works best for me.

 

[ALRedneck]

Higher octane will resist higher heat before it detonates. Higher compression will create higher heat which in turn will donate fuel before the spark, that's spark knock or pre ignition. That's a very basic explanation and I'm sure someone will come along and argue it or expand on it.
Gotcha! So the 89 ignites at the right time v 87 igniting prematurely?
Sent from my Pixel 4 XL using Tapatalk

 

[ALRedneck]

Higher octane will resist higher heat before it detonates. Higher compression will create higher heat which in turn will donate fuel before the spark, that's spark knock or pre ignition. That's a very basic explanation and I'm sure someone will come along and argue it or expand on it.

Sent from my Pixel 4 XL using Tapatalk

Gotcha! So 89 will ignite at the right time v 87 igniting prematurely?

 

[ALRedneck]

this is going to open a can of worms on a ridiculously long thread on miles per gallon on a power wagon already lol

but I will comment as I have on the heavy duty section. If you want the eco mode to work without vibration and to save you 2-3 mpg when engaged you will need mid grade as it is recommended in the manual. I took a 3k road trip and included mpg in my experience. I wrote a whole thread day by day of my trip into the smoky mountains. What I did not know was how my wife got 2-3 miles more per gallon then I did and was not till 2 weeks after I got home I realized that when I selected 8th gear ( so I could watch the down shifting patterns while in the mountains) it turned off mds. And when my wife drove she just put it in drive a let it alone. Since my trip ( in my 2019 with the 8spd) I tested it a few ways. And 89 works best for me.

Bet if I modified tires or exhaust I would notice a difference with MDS on 89. I’m going to just stick with the 89 anyway. Truck is probably will be happier in the long run with 89.