2006 RX 330 has 4 sensors to deal with 2 upstream AF left and right, downstream sensors also left and right, no clue where it is located, downstream is after cat converter and upstream is before the converter, any body has ideas ?

 

All the information you request is already here at CL. You just need to search for it. For example:

https://www.clublexus.com/forums/rx-...rt-number.html

Sewell is also a good source for information:

http://lexus.sewellparts.com/oem-cat...X330-2006.html