Precat 02 sensors going inactive

I been trying to track down a possible exhaust or vac leak. I did a smoke test on the engine and could not fine one. I put headers and highflow cats (smiedmann) in some months ago and car had no issue.

The car runs great but i keep getting an eb code for bank 1 alone. Well today i took out sensor 1 and replaced it with another i had.

I let the car run for quite sometime and came back and it had bank 1 and bank 2 permissible range exceeded. I was checking intermittently to see the voltages on the pre and post cats and they were fine and fluctuating on both banks.

Then i when i came back, they were both at 0 and showing as inactive. I didn't do anything with bank 2 sensor 1 so not sure why it is showing now when it didn't before.

I did have the coolant sensor disconnected so that the fan ran the whole time and heater on so car didn't over heat. I doubt that would be the issue anyway.

Anyone have an idea why this could be going on?

I know there is a service bulletin for a ecu glitch on these cars. I'm going to smoke test the exhaust tomorrow to make sure but i retightened the headers and checked with shop vac and soapy water and found a pinhole leak that i fixed with "acccusti-seal".

ANY idea would be appreciated.

Thanks.

Precat 02 sensors going inactive