So this morning this code appeared. A month ago I hade the code and replaced all my O2's. I have Cattman headers and Cattman hi flow cat which is about 5 years old. I knew the rear o2 was dead as it had no signal. When replaced it showed signal but the cat reading was all over the place. Code was cleared and I passed emissions. But now the code is back.

I've searched and I've only seen posts on precat replacement (which I dont have). Could this be a rear cat issue as well?

Also wanted to add I had misfiring issues previously which has been now corrected.

 

Have you checked your fuel trims?

 

I have not. I know the torque app I can check the trims. What am I looking for?