BigBirdLS1

I have been chasing an 02 related problem for like 3 weeks now. To start it off I threw 02 code for malfunction on bank 2. I bought some brand new Bosch sensors and replaced both of them and the very next day I got a SES light and I checked them and I got codes for both banks. I yanked the Bosch PoS's out and I ordered some OEM denso sensors. I recieved them today so I put them in and cranked the car it seemed to run fine. I data logged some info at an idle and I saw these reading
Bank 1 Sensor 1: the numbers varied from 35mv - 900+mv
Bank 1 Sensor 2: varied from 440mv - 455mv
Bank 2 Sensor 1: varied from 440mv - 455mv
Bank 2 Sensor 2: varied from 440mv - 455mv

I have two concerns 1. Why in the world does the one sensor read so differently that the others and 2. I only have the upstream sensors plugged in as the rears aren't even there because of the longtubes but I am getting readings from them. So why is that happening and insight or opinions will be very appreciated. Thanks Guys

pber13

the only code it's throwing is for the 02 sensors? can your datalogging software log the fuel trims? that would let you know what it's doing. just because it says 02 sensor malfunction doesn't necessarily mean the sensor is bad. in this case the sensor is reading out of its normal range.