I have 2002 Dodge ram 1500 ext cab 4x4 with the 5.9 gas motor. I have swapped out all my spark plugs as well as the wires with them and i have a regular k&n air filter with it but i am still only looking at about 14 mpg. I have looked into the super chips website and into their chips but they didnt get very good ratings on them, one was a 2.86 and the other was a 3.75, couldnt look at exactly why they got the ratings, and i was wondering if there is anything i could put on my truck to help get better gas mileage. i am currently looking into putting duel magna flows on my truck as well.

 

Superchips is gonna add about 40 HP and 40 TQ but not help a whole lot with fuel economy. There is little that will help short of spending major coin that will take years to recoup in fuel savings. Tuners usually get poor ratings no matter how good they are (and in the case of the 5.9 Superchips is the best one short of a custom tune) because people expect HUGE gains from a $300 tuner. They think they can spend $300 and see the gains that $3000 in ported heads, ported TB and a cam will get you - Ain't gonna happen and they tend to be disappointed.

At 14 mpg you are doing VERY WELL with a 5.9 Magnum (LA360) engine. It's a tank and with good care will last forever but power per CI isn't a strong suit and fuel economy is downright poor in this engine. But you gotta consider that this engine was designed in the late 1960s and has only undergone minor changes in all those years like adding a throttle body and fuel injection. Gas mileage WAS NOT a huge concern when they designed it seeing as gas was about 50 cents a gallon.

I've found that about the only mod that pays off in fuel savings is to ditch the clutch fan and install an e-fan. You'll gain about 2 MPG in town - but not much if any on the open road. Due to the relatively low cost of an efan (under $300 in full kits and can be under $100 if you go the "pic 'n pull" route on a used fan) it can save you enough in fuel to pay off - plus there are a few other advantages.

I had a '98 RCSB 5.9 4x4, lifted on 35" tires and saw single digit fuel economy to maybe 12 mpg on the highway.

Proper maintenance and running the tires at least 80% of maximum PSI is about the best you can do. Going with synthetic fluids where you can will also help a little. Save your mod $ and put it in the gas tank. Probably not what you want to hear, but that's how it is...

 

for a 4x4 that is pretty good. i think the only way you could get any better mileage is if you had the 5.9 diesel. i think the biggest thing you can do that is free is drive like an old person. accelerate slowly and if you see a red light ahead let off the gas and coast.

 

I also think you are doing very well, however if you are so concerned about gas mileage (given your vehicle), you could take a stroll down to the local Toyota dealer and buy a prius.

 

Yeah, my dads 98 5.9 was never good on gas.

 

I had a '97 Extended Cab with 5.9 and would've killed to get 14 mpg's out of it.

 

^^this! Or buy a Smart Car! I'll stick with my 15mpg Hemi and let the kids have their Smart Cars! I'm not gonna look a fool in one! LOL

 

Every time I see a SMART car I see a death trap

 

Or you could do a Cummins 4BT swap lol. That would help the mpgs

 

Actually Smart cars are underpowered and really not that good on gas. There's a guy at the golf course who has one and gets about 26 mpg with it. Hell before I sold it, my step-dad left me his '01 Accent, a LOT bigger than a Smartcar and I got 33 mpg average and could easily get 40 on trips. Kinda wish I kept the thing now.

But yeah I know, if the OP had posted in the 2nd Gen section there would be a LOT of guys envious of 14 MPG with a 5.9...