i just joined.......i just got a 2005 dodge ram QC SB hemi auto. with 55000 miles. its stock and has 3.54 gear and 285/70 17 tires. the best i have ever got was 15.5mpg and that was all highway....most of the time its 14.5-14.9mpg. some times i get as low as 12.5mpg if i go to a sh*ty gas station... i use 89 octane fuel. are my gears to tall? i know taller gears should make you get better gas mileage but there so tall that any kind of a hill i get to it shifts down 1 or 2 gears. its like 1500rpm at 60 mile an hour.
Thanks

 

There are some things you can do but how much of a change in milage you will get is the question. First of, has the oil been changed? If it doesn't already have it I would go to synthetic oil. I did and my truck ran smoother and was a little stronger and I picked up some on the milage(.5 to 1). When was the last time the plugs have been changed? If you don't know I would change them. Only thing is unless they are in bad shape you won't gain on milage enough to notice. Next, change the drive train fluids. Front and rear diff(if 4x4 if not then just rear diff) trans fluid and filter. It has been noted on this site some that have changed these fluids to synthetic have gains in the mpg's. And last but not least does the air cleaner need changing? I assume you have the stock air box. There are alot of things to be done but in the end its still a truck and it will never get great milage so after you have done what you can to improve the milage..... IT IS WHAT IT IS.. Learn to live with it or go buy a car. Hope this helped some....

 

well if it makes you feel any better you are getting better than I am, I get about 12 on the Highway and between 8-10 in the city depending on the snow right now.

 

The best mod for MPG that I have done is an e-fan. Showed the most improvement out of everything thusfar.

 

I am waiting for the how to for putting in the e-fan becasue I want to do that. how is it coming off_road-Teacher?

 

I didn't get my snow day wednesday, only a delay so I didn't get to do it yet. It is on my list for this weekend. Sorry for the delay but I will have it done before monday.

 

I think the best MPG gain was when I bought my 95 stratus 4cyl.! 33mpg's
It cost me $500. When gas was $4/gal, I got my $500 back in 2 months of saved gas. The car paid for itself!

 

Frist, congradulations on your new truck. Frist thought is to give you hope. I suspect your weather is similar to mine in northwest Jersey. During the winter I average about 1.5 - 2 MPGs less than in the warm weather. This is due to a combination of the winter blend gas and the engine running rich until it nears "normal operating" tempiture. I can get about 17-18 MPGs if I keep speed below 70, after that it drops like a stone.

The 285/70R17 did not come standard. Frist, the more agressive the tire, the lower fuel mileage. Same goes for weight. The heavier the tire, again, reduced mileage. (Lt tires can weigh a lot more). Additionally, the oem tire was most likely a 265/70 or 31.5 inches. The 285/70 is approximately 33 inches. That is 5% bigger, was your speedometer recalibrated? If not, your speedometer is slow by 5% (reads 66, actual 70) and the gas mileage calculation has to be adjusted up 5%. The good news is that you will get a few more miles on the 7/70 warranty. You did get it transfered, right?

My 2004 drive train is the same as yours and I went to the 275/60R20 that is also 33 inches and I do have some wandering when going through the hills, but I could eliminate most of it by switching the to the haul/towing mode. It holds the shifs longer. It is also more frequent with the winter blend of gas since it has less BTUs.

Thoughs on improving gas mileage

(1) Plugs are scheduled to be chaged at 30,000 miles, if you have the orginal plugs, you will pick up some mileage with the change.
(2) As already stated, going 100% synthetic gave a me a solid 1/2 MPG and fewer oil changes (normally go 5-6K).
(3) The greatest gain was by increasing the PSI in the tires. I run 44 front and 38-40 in the rear. The tires wear even and I picked up a full MPG. In my opinion, it takes the turns much better too.

Happy Hunting.

 

yeah, I personally think an e-fan is about the only mod that would make back it's cost to justify doing a mod solely for the mpg gain. Not that the gains are huge, by any means, but the comparative cost for the modest mpg gain in probably worth it.
Anything else, realistically, would take longer than the avg. life of the vehicle to recoup the cost of the mod.
Just the basics. Tire pressure, tune ups, synthetics, etc. will yield you the best mpgs for the buck...

 

Well put Hammer!