OK, so I did the usual, but am looking for possible "larger" changes for my 2001 Dodge Ram 1500 4x4 w/ 318 (pig). Meaning cams/lifters, gearing, new wheel bearings, etc. Do you think there are any benefits to doing any of these for better mileage? I know the cost to savings ratio won't be good, but if I can keep monthly costs down, that will make things "feel" better. Here is what I have done so far and haven't got ANY increase in mileage (and PLEASE don't tell me to get a CAI, those have been "busted" several times in real world dyno's and testing).
1. New plugs and wires, (high quality, forgot brand but expensive), cap and rotor (Accel)
2. Accel ignition
3. 180 degree stat
4. New oil and filter
5. New tranny filter, flush, and oil (x3 because of adjusting shift points)
6. New water pump
7. Checked O2 sensors and they are good (unplugged in exhaust and still ran same)
8. Dual exhaust (already on truck when I bought it)
9. Tuner, set to better mileage (no difference between better mileage and performance setting)
10. Good driving habits, though most driving is in city.

I get about 10 mpg city and 11.5 hwy. It IS a 4x4 (I know...but it is, so I have to deal with that). I use 91 octane also.

Any idea if a cam, adjusting lifters, modified kegger, MAI, plenum fix, etc... would help mpg?

I know, I could sell it and get a two wheel drive hybrid, but I don't want one, I just want better mpg with a 4x4 beater Dodge pickup. I like it.

 

Cheap copper plugs. Ngk, champion(my fav) or autolite
put the 195 temp stat back in
Not necessarily 91 octane gas. but find ethanol free gas

What kind of tuner?

Your mileage is pretty good really.
What size tires?

 

I'm getting 14½-15mpg on 91-92 octane... over the past year I've change all sensors except the cam position sensor... I use NGK copper plugs, and the rest is in my sig.

 

Unplugging your 02 sensors will not tell you if there good or bad. If your 02 sensors have more than 80,000 miles on them, there bad. A bad 02 sensor wont always throw a code, but when they get lots of miles on them they get lazy and don`t function as they should.
You can get new 02 sensors from rockauto.com for a good price. Don`t use Bosch 02 sensors, they don`t work well in our trucks.