ORIGINAL: bb816331

Hmm...well i try going to Motorcrafts website to find the oem part number. It shows two different ones for downstream, and one for upstream. Which one is it??? Here's the part numbers:

RR - DOWNSTREAM - LH - XR3F-9G444AA

FRT - UPSTREAM - XC2F-9F472AA

RR - DOWNSTREAM - RH - 1R3A-9G444AB

Any idea of what these cost at the Ford house (other than an arm and a leg...?)

ORIGINAL: art02gt

if it's a rear sensor, then it's a down stream. it just depends on wheather it's the left or right.Ask the place where you gotthe diagnostics test, they should be able to tell you if it's the right or left. Now that i think about it, I believe oreilley's sells motorcraft parts, they're prices are usually lower than the dealership.

ORIGINAL: bb816331

Well the dealership told me Bank 1 rear sensor. I'm guessing that's drivers side...Er, uh, I don't know which way you look at the car to tell left from right...so which is it? I'll check around for motorcraft parts, too.

ORIGINAL: bb816331

Ok, I found out that if you click on those extremely long part numbers I showed above, it lists the correct part. So, for future reference, here are the correct part numbers in case anyone ever wants them:

DY-1038 - Motorcraft: Rear ; Downstream-Left Hand
DY-1104 - Motorcraft: Rear ; Downstream-Right hand
DY-1039 - Motorcraft: Front ; Upstream

Quick question...why can the front sensors be the same, but require different ones for the back? [>:]

ORIGINAL: black35th

No, like I said in the post right before this..........Bank 1 is the passenger side, bank 2 is the driver side.

You need to replace the passenger side rear O2 sensor.