I have a 99 Z28. When I get on it really hard a few times in a row the SES light will come on. I had the codes read and it was 02 sensor bank 1 sensor 2 and 02 sensor bank 2 sensor 2 codes being thrown. Once I drive the car around for a little while without getting on it the SES light will go off. While the SES light is on I can tell no difference in the car. It runs fine, pulls hard, gets the same gas mileage so I am pretty sure its not affecting anything but I don't like the SES light coming on.

Correct me if I am wrong but Sensor 2 is the 02 sensors after the cats right? Could this just be that both bank after cat 02 sensors are bad? What do you think I should do? Thanks in advance.

 

You are correct that those are the after cat sensors. Which code did it throw?

 

I think it was PO137 and 157 if I remember right.

 

Those are the codes for the after cat sensors. After a header install it is often necessary to disable the MIL on those sensors. I had to do it with mine to stop the annoyance. If you haven't made any mods, you may have something else going on.

 

Funny thing on this, I read on the forums here that a dirty MAF could throw those rear 02 codes so I took my MAF and cleaned it with some Q tips and some electronics cleaner and since then it has thrown 0 codes and I have been getting on it pretty hard. I guess maybe I fixed it.