now i know that the rams aren't praised for the great gas mileage...thats not why i bought it, but the mileage just isn't where i think it should be. driving highway and/or city the truck always gets roughly 12 MPG. its got new plugs, wires, cap, rotor, pcv, oxygen sensors, and throttle position sensor. there should be some kind of a difference driving on highway compared to city. any ideas?

kevin

 

My problem, LEAD foot, I never get any better than 10....in Nocal, AT 2.30 a gallon.....

 

its doesn't seem to matter how i drive either....lead foot or granny style. its always right at 12 mpg

 

What's your tire size, and what gears are in your axles? I'll guess you went up to 265 or 285 tires right? Probably have 3.55:1 axle gears. If you run 285 tires, you need 4.10:1 gearing for optimum efficiency. Plus, your odometer will be off if you haven't recalibrated your speedo, so you're actually driving farther than you think, and getting slightly better mileage than you think. If you're running 285's with no speedo calibration, you're off by about 7-8%, which comes up to about 1.5-2 mpg for an average tank.

 

i'm running 265's and whatever the stock gearing is... assuming to be 3.55:1. when i bought the truck the speedo wasn't exactly accurate so i took it to the dealer to have it recalibrated. as of right now its correct. with 265's should i change gearing? or would that even make a difference?

 

3.73:1 gearing is about ideal with 265's. It's not THAT huge of a difference. You'd probably gain 2 mpg with the change, but you'd spend a large amount of $$$ to do so. It would increase your accelleration though.

 

how much is a large amount of money? to get an extra 2 MPG would be absolutely wonderful. i drive 50 miles round trip everyday. school and work then home. so you can imagine, it doesn't take long to go through a tank of fuel.

 

To do it right, you're looking at about $500-600 in parts for new ring and pinion gears and bearings for both axles, plus whatever a shop will charge you to install them. Usually around $1000 total for parts and labor. You can save about $100 by reusing your stock carrier bearings and it won't be that critical, but to do it right you should change them.

I'm not saying this is 100% guaranteed, and I'm not saying it's the only thing to try. I'd put a stock thermostat back in it to start with. Running the engine at a lower temp will make more power, but engines are designed to run at a certain temperature for optimal efficiency. Maybe a stock thermostat would help the mileage a little.

 

yea, i've wondered about the thermostat. I was thinking i'd change it back within the next couple of weeks. i didn't really notice any extra power.... thanks for the info

kevin