O2 sensor upstream or downstream

[Kermit]

So after replacing the egr valve last week and clearing the codes I still have rough idle and the check engine light came on again. Stopped at advanced to have the codes read and came back with p0401 exhaust gas flow insufficient, p1131 lack of heated O2 sensor bank 1 sensor 1, switch indicator lean. P1151, lack of heated O2 sensor, bank 2, sensor 1, switch indicator lean. My question is this... First, how many O2 sensors are on a 99 expy 4.6 4wd? And 2. When i look on parts geek at O2 sensors in the choices they indicate upstream or downstream... How do I know which is which by those codes? Are there any O2 sensor diagrams out there? These are the choices given for O2 sensors from parts geek (feel free to suggest which ones I should get)
http://www.partsgeek.com/ss/?ssq=Oxygen+sensor&make=ford&year=1999&model=Expedition

Thanks again guys (and gals ).

 

[Bedrck47]

A while back I suggested that you get a copy of THE FORD SERVICE MANUAL ON DVD Had you obtained this manual it would not only tell you the amount of O2 sensors in your expy it would show you the locations of the O2 sensors and also have wiring diagrams The Manual is priceless

 

[Dewayne]

4 oxygen sensors , b1 s1 passenger side before cat b1s2 pass side after cat. b2s1 drivers side before cat b2s2 drivers side after cat.

 

[Kermit]

Thank you dewayne for the info. Much appreciated

 

[Kermit]

Bedrck while that is true, 1, did u really need the $25 you woulda charge me for the DVD, and 2, if I got the guide I'd never get to talk to the lovely people on this great forum

 

[Bedrck47]

For one the price I told you was $20.00 plus by having the manual you would be on the same page as many of us are on and have a better idea of what you have no idea about. #2 the only time you come on here is when you want something from the lovely people on here Or to have them find information that you could look up if you had the manuals.

You would also find that the O2 sensors are referred to as

Heated Oxygen Sensor (HO2S) #11 or #12 0r #21 or #22

And did I need the money Not really but of course I could always use it. But what difference would it be if you purchased it from me or somewhere else At least I would be here to help you But if you went elsewhere just what help would that be for you.

 

[rjdelp7]

A while back I suggested that you get a copy of THE FORD SERVICE MANUAL ON DVD Had you obtained this manual it would not only tell you the amount of O2 sensors in your expy it would show you the locations of the O2 sensors and also have wiring diagrams The Manual is priceless

The time spent typing sarcastic, condescending BS, you could of answered question.

 

[Kermit]

Thank you RJ. kinda how I felt but didn't wanna say anything.