97 ram 1500 4x4 5.2L auto 245/75/16
I bought it with 208,000 miles and was averaging 12mpg. changed the air filter, spark plugs, wires, distributer, plenum fix and 180 thermostat. currently has 217,600 miles and i average 14.5-15.5 mpg. best was 17.2 at 65mph behind a semi trailer.

I have a plugged cat and original muffler. hopfully knocking the cat out will improve mpg and power slightly.

 

'00 ram 2500 4x4 cummins 6-spd 315/75R16 4.10

averaged 17mpg when I bought it...

modified it quite a bit since then and more than doubled factory HP and torque @ the rear wheels...

now it gets 13.5-14mpg average with over 538hp/1078lb/ft tq @ rear wheels.

 

Hollowing out the cat will help a little if its plugged. The computer will take a while to get used to it tho. New O2's might be a good idea as well. That plenum was a joke. I went with an aluminum belly pan from Hughes Engines. Stood up to the Kenne Bell twin screw for a few years...

 

I was getting around 17mpg on mostly backroads in my 98 1500 318 auto 41k miles

 

98 with only 41k miles??? Sweet!

 

1997 1500, ext cab, short bed, 5.2L 2wd. 8 inches of lift with 315/70/17 Grabber Hts tires, 4.56 gears, Gibson exhaust, specter intake. I'm getting just over 11mpg in the city and 15.5 highway. 17 without my rollbar. Gear change and tires only brought me down 2mpg highway and 1mpg city. Not bad

 

Well, my 2011 1500 Crewcab is a year old now. It still is getting between 18-19 on the freeway. I am thinking of adding a JET brand programmer. I don't need the extra power, but can it make the engine run more economically? Has anybody used one of these? If it can't help with the better mileage numbers, then I will probably just sell it to somebody to help them make power. John

 

You might want to pose that question to the 4th gen ram section.

 

99 5.2 single cab 4x4.... a hair over 10 miles a gallon.....

 

I got 15mpg highway with my 285s. I have a new set of 245s on her now and haven't had a chance to get a new mileage.