ok i know virused will get pissed off that i didnt search this, sorry man, but i dont exactly have the time to search this to find the answer im looking for, college and a job has taken over my life... my fuel milage just went to **** in the matter of a week, i got the feeling one of my o2's took a crap, 73K miles on the original factory sensors... i know one controls my air fuel ratio if im not mistaken, anyone remember which sensor is this?.. thanks

 

both do..

if you think your o2s are bad replace them

70K is when your suppost to replace them all 2 or 4 depending onyour exhuast setup.

They are about 50$ each so have fun.

 

yeeep... 4... $200 i dont have... fuuun.. anyone else?

 

you can try to take them out and clean them...

 

Yea, like User2006 said, all the oxygen sensors (2 or 4) play a role in the air/fuel ratio.
And yea, they recommend to change the O2 sensors between 70-100K miles. (I've got my two sensors lying right next to me, just got my old rear sensor to break loose, had to heat 'er up real good, the partto attach the socketto rounded right off[:@])

Here are tha main factors that effect the fuel system (close to this order): right foot, o2 sensors (with engine at operating temp), MAP sensor, engine coolant temp sensor, intake air temp sensor.

 

thanks guys.. i thought just one of the sensors just read what was going on and didnt affect the air-fuel mix... so should i go back to stock sensors or find after market direct plug ins.. i will not solder something with a voltage line with such a small operating window

 

I read a few years ago that Bosch oxygen sensors weren't good (neither are their platinum spark plugs, wow... the main things they make!).
I ordered NGK O2 sensors (which I'll be installing with my NGK V-power spark plugs, probably tommorow) from Summit. About $48 each, which was less than the cheapest sensors at O'reillys, NAPA, or Autozone.

 

Ichanged both of my o2 sensors on my 2000 dakota 3.9. i bought them from car parts warehouse in euclid ohio for $69.85 for both (my friend works there). They are from Denso. work great they even come with a tube of anti seize. and i also checked the denso website out they have them on there also .
http://densoproducts.com
2000 3.9ldakota club cab 4x4 236k and still running strong

 

ngk's are supposed to be the best o2 sensors for the 3.9/5.2/5.9

 

wow i appreciate the help, thanks boys.. yeah but my fuel milage kinda went back to normal.. something's up in that circuit, im gonna crawl under there tomorrow and take a peak at the sensors and the connections just for giggles, cause i read in the repair manual that the o2 sensors also take an external oxygen reading to compare to the exhaust, so im gonna see if that is plugged with mud or something, hell it beats throwing money away without giving it a shot