I hadn’t gotten a response to my other thread so figured I’d directly address this question.

I installed the anti fouler fix for my P0420 code. I used the two foulers stacked on top of one another as recommended by many.

My CEL has stayed off (for now) but I have a noticeable loss of low end torque. It’s not huge but I definitely have to push the pedal further to get and maintain power.

I’ve been told the down stream does not affect fuel trim and air/fuel. But read somewhere else it can account for some fuel managment.

Anyone else hAve this experience? Is is because maybe the o2 sensor is spaced to far? I don’t want to run lean or damage my engine.

Thanks