5.9L SLT with Tow package and awd. 18-23mpg on the instant monitor @ 70mph cruise. This was after the new map sensor.

Before the new map sensor 12-14mpg on the instant monitor @ 70mph cruise.

 

Holy crap, 18-23 mpg? that's insane from 12-14. I just replaced my map sensor. I do noticed improved MPG, but nothing to write home about, I was drinking between 8-9mpg if just driving in the residental area. With new map sensor, it pushed it to 10-11, much closer to normal for residential driving for this 5.9. I wonder if I can push the MPG higher by replacing the O2 sensors then?

BTW, what axle ratio do you have? R/T's come with the 3:92 ratios.

 

I don't think thats right?

 

Yes, 3.92 gears. I'm talking about highway cruising at 70mph. I don't even worry about in town driving to much. Most of my drives are highway. The 18-23 mph is the instant mileage reading on the little trip computer overhead. This is on a flat road.

Kensai, with you being in the Denver area with all those steep mountain grades, your mileage will just svck a$$. lol

 

Uh, You read my post incorrectly! haha, look at my sig, I am from DFW. So most areas, we are flat here. I am spending my maintenance budget on my truck in preparation for a 10-12 hour trip from DFW to Denver. So I want to maximize my MPG as built from Dodge for the R/T. I will try to squeeze as much MPG and get as close as the rated 17 mpg rated highway mpg the R/T is rated for. If I can get more, then I am more than happy! But driving in the Texas area, I usually get 13-15 highway. If I get a slight improvement driving residental, I would assume I may bet a bump to 15-17 mpg highway. I won't know this aspect of the mpg until I actually make the long distance trip. Nowhere in Dallas I can maintain a good consistence speed for at least 20 miles to get a good highway mpg calculation.

I made up my mind and will get the O2 sensors replaced. I think at this point, all sensors on my truck has been replaced now. Ooops, except for the IAC sensor but I think that sensor is still working fine.

 

you sure the R/Ts are rated for 17??? bc i still have the window sticker that was in my truck on the dealer floor and it says 13 city/17 highway for mine, and i got the 4.7

 

Instant mpg numbers are usless. Must calculate whole tank to be accurate AND you must calculate it by hand. Miles driven on that tank divided by gallons it takes to fill it back to full.

I get 14 city and 15 hwy. The 4.56:1 gears killed my hwy mileage (was getting about 17) but didn't change my city mpg. (But did make it MUCH more fun to drive.) I have gotten as little as 6 mpg on one tank. That was when I was trying to finish off my tires before I bought new ones. That was fun.

I get 8-9 mpg pulling my stump grinder which weighs in with the trailer at 7,000 lbs. I don't use the Durango to tow anymore as I now have a 2000 Excursion XLT 4x4 V10 with 4.30:1 gears. That vehicle is a beast. I had it on the scales last week at over 21,000 lbs (truck and trailer) and the next day probably had 3,000 - 4,000 more on it!

 

First off never beleive the overhead computer!

Kensai I think your over on the expected mileage. 15 maybe pushing AWD.

I still think your plugs......... and before you write an essay on this it's just my opinion.

Although one way to squeze a lil more out is to take your foot off the throttle......LOL



Scott<------- 21,000 is just plain sick!

 

i got the 4.7L 4x4 lifted with 32" tires. i get about 13-17 between city & highway driving on each tank.

 

I don't believe the overhead, but when comparing before to something you have changed it is comparing apples to apples and is a good way to gauge if what you have done has made a difference in mpgs. I just added a magnaflow muffler with 3" pipe,summit(kn) drop in filter, and hypertech tuner and I am seeing 19-21 at 40 where I used to see maybe 10-11. Not to mention it shifts very nice now. No new hwy numbers as it is too windy to compare to sunday.