Something is wrong with my truck. I get bad gas mileage
 

Alright, for the 1,000th time I need help with gas mileage. Driving my truck like a grandma... and say 70% City and 30% highway. My last fill up... 11.9. Something has got to be wrong. Its a 2wd, 5.2. I did the plenum..

I unplugged the original pre cat o2 sensor, and let it idle for about 15 minutes. Nothing happened. The RPMs didnt change, no CELs.

Ive given the truck a complete tune up, rotor, dist, wires, plugs, K&N filter....

I was thinking maybe MAP sensor or the 02 sensor. Any ideas?

Its got 81,000 original miles..

Your driving a 2gen Dodge Ram, there just hogs on gas man. 11mpg is about avarage for us.

I changed my O2 sensor and gained 2 mpg.
Thats with blown plenum and 176,000 miles.

Dave

My 5.9 4wd does better than that and I'm not gentle with the throttle. Something is not quite right

unless you've got a lead foot and/or huge tires, you should get at least 13. if you're current on tune up - try replacing the front O2. i just replaced mine and naturally ordered the wrong one. my plug is square and i bought the round one.

you can follow the wire up to the connector that's conveniently snapped into a connector on top of the transmission, and see which one you have. it was obvious that i was going to either break the plug, or break the plastic stud that holds it in place, so i cut the stud so i could turn the connector to where i could see it. slide the red tab out, and then sort of pinch it.

mine had 4 wires. i think it was 2 whites, 1 black and 1 gray. i ended up just splicing my old connector onto the new O2.

12 MPG is pretty good.

11.9 is above average. At best you can get 16 MPG, and that is what I got with my old 1996 4x4 5.2. I had the mopar performance PCM, MSD 6AL ignition and coil, and 4 hole injectors.

So unless you have about 1000 to spend, you are stuck at 12 MPG.

So you think O2>MAP? Do any of yall remember the thread where a guy replaced his map just because it was old and got alot better MPG?

I remember reading that thread.
I just havent done map sensor yet.

Dave

And for 02 sensor brands which is better?

NGK or Bosch

At idle, the computer basically ignores the O2 sensor..... Especially in park or neutral. It should whine about not getting ANY signal from it when you unplug it though......