i recently drove from san diego, ca to san jose, ca (about 500 miles) and almost made it on one tank of gas. i made it to salinas, ca which is about 440 miles from san diego and had a little under an eighth of a tank left. i figured out the mpg when i got home and it came out to about 18 mpg. i was doing a constant of 75 mph the whole way. i had at the time 31" goodyear a/t tires, flowmaster muffler on 4 inch exhaust, k&n cai, and a superchip set to fuel economy. i was jumpin out of my seat when i saw this happen! i almost waned to drive until it ws empty just to see how far i could go.

 

Ain't highway mileage great?

 

gotta love it. granted around town i get about 14. i just love to see that number 18

 

Good grief, you must be sporting a woody! My Dodge would pretty much pull 15.6 on the highway, but this past weekend of hauling some VW's on my trailer have shown my transmission is KAPUT. I'm lucky to be pulling 9.5mpg with a load, whereas before I was getting high 13's.

 

I'd love to get that kind of gas milage. It seems like with mostly highway driving and a little city I get around 12.5mpg usually. I once got 14.25mpg on the highway. Now this is with a 5.9L and 33"s with 4:10 gears running 70mph on the interstate. I just don't see how people are getting this kind of gas milage. I wish I got it.

 

m/t tires are a killer for mpg if you have them

 

I recently was on the highway for a 75 mile trip and went 70mph the entire way. I averaged 17 mpg the entire time with 35" tires and 4.10 gearing. I think with the bigger transmission, the headers and complete exhaust, with the recent tune-up, this is allowing me such great numbers. I am getting 12.5-13 mpg in the city as well. I've been very happy.

 

I only lost about0.5 - 1 mpg when I switched from my bald 265 bald all terrains to my 33"swampers. Hell I think I might have got itback when I switched from the stock air cleaner to my round one.

 

With a mud tire or an offroad tire, they just don't have any kind of exclusive design to keep it aerodynamic. When I bought the truck it came with Dunlop Mud Rovers. Not the most aggressive mud tire, but it sure isn't a smooth ride. I can literally feel the tire pulling the truck around. The only good thing about the tires, is they make braking easy I'm anxtious to get the tires off this fall though. Procomp All-Terrains seem to be my best bet. I like the tread the most. They ride smooth (which is most important to me), they have a 50,000 mile warranty on them, and to boot, they are Severe Weather Rated. I live in Maine, so that's important to me. The mud tires suck in rain, suck in snow, and are terrible in ice, they pretty much are a useless tire unless your "mudding"...which I hardly do. I'm curious to see how my truck will drive and if my mpgs will go up when I get a smooth treaded tire on the truck. All I can say is that at 75mph on the highway, those 35" mud tires really start to let ya know they are there, and I cannot stand it.

 

I have 33" BFG Mt's on my truck and at 75mph they start humming quite a bit but other than that they aren't bad at all.

Anyway I keep hearing about keeping up on maintence to get good gas milage and I do that more than most people. I have a fresh tune up as in probably 1-2k miles ago. I put MSD 8.5mm wires on, Napa dist cap and rotor, and Champion Platinum plugs. I also put a Napa PCV valve in there and a new fresh Edlebrock Air filter in my Edlebrock Pro Flo. I had probably 40k if that on my last set of MSD wires but something looked like they chewed through them or something so I replaced them. It was just the edge of the shielding and didnt' seem to be missing but I figured I minus well replace them.

I also for mods have a Edlebrock Air hat, APS Pleneum kit(installed about 1-2k miles ago), Flowmaster 40 exhaust, Hypertech PP3 programmer on the Performance setting running 93 octane, Auburn LSD in the rear, Royal Purple fluid in the front diff, and engine. It used to be in the rear but since you aren't supposed to run synthetic with the Auburn it's no longer in there.

I have more mods than that but basically thats the ones that should help gas mileage. I don't have headers though. Any ideas on how to get any better gas milage or am I getting about whats normal?