I have a 2001 chevy blazer 4x4 2door and i had a code say bad 02 sensor bank 1 does anyone have a picture of where it is or how to change not very sure how to do it?

 

What was the specific code? On an '01 (any '98+), you will have:

• B1S1 - Bank 1 Sensor 1 which is the driver's side fuel management O2 sensor located on the driver's side of the y-pipe a few inches down from the exhaust manifold.
• B2S1 - Bank 2 Sensor 1 which is the passenger's side fuel management O2 sensor located directly ahead of where the 'Y' is on the y-pipe.
• B1S2 - Bank 1 Sensor 2 which is the catalyst monitoring O2 sensor which is located behind the catalytic converter. (could be B1S3 on the 98-2000's)

So as you see, you have two Bank 1 possibilities.

 

how hard would it be to take them all out and clean them i think there really dirty or would it just be better to replace them ?

 

It is highly likely that you will do more harm than good by attempting to clean the sensors. Some have had luck cleaning them though.

How I would typically diagnose this problem without using my scan tool would be to swap the sensors side to side (in the case of the B1S1 & B2S1 sensors). The B1S2 sensor is the post cat sensor which only monitors the catalytic converter and has nothing to do with fuel management. But I would have to know the actual code to recommend further.