Originally Posted by Bo0stin5STI
The tune with AP's turn that code and a few others "off" so they can't come on again.
The issue with not running o2 sensors is the fact that the car uses all inputs to correct fueling/AFR along with others. Not running the sensor can cause "lean"/"rich" conditions.
Leaner is meaner but closer to destruction!
As far as I know, the rear o2 sensor is only used for emissions detection. The front o2 is used for closed loop fueling, which affects afrs in cruise and light load.
The op should try stacking another non-fouler underneath the other one. I'm running catless, and the dp bung is as long as 2 non-foulers stacked together. I've never had a code thrown.