B4C z28 o2 sensors

[Tprwells]

Ok, so Im getting codes p0131, 151, 420, 430. Anyone know or can tell me which o2 sensors I need. I will start there and replace both of those first (bank 1 & bank 2). I noticed there are a few types to include: direct fit, 2, 3, 4 wire. And is it the same ahead of the cat and behind the cat? Any input from anyone who knows would be awesome! thanks a ton!

[Tprwells]

I might have my answer on a few sites. However when it refers to sensor 1 and sensors 2, that refers to either upstream or down stream right? Anyone? And where is piston #1 driver or passenger side. I'm a new owner as you can tell!...lol

[2001NBMZ28]

Bank 1 is drivers side, Bank 2 is passenger side. Sensor 1 is precat, Sensor 2 is post cat. Cyl #1 is the drivers side front. 1-3-5-7 drivers side front to back, 2-4-6-8 passenger side front to back. P0420 and P0430 are cat inefficiency codes, usually not the rear sensors. How many miles on the car? Cats are covered up to 120K.

[Tprwells]

97k...car runs awesome and very strong. Just had that SES light come on past couple weeks. Thank you for the info....very helpful brother