I just got my car back from dealer today after oil change and brake flush. Along with those I wanted them to check the o2 also, just make sure is at
3% or better. This is what they found with the secondary air pump disconnected and the 02 sensor unplugged was at 7.85% and HC=560 PPM.
Now after ajustment the CO is at 3.3% and HC 45 PPM with the air pump
connected and senor plugged. Should I leave them back unplug since I am
running with header, 1 bar spring and no cat ? My dealer said the car is
running much smoother now, and I don't get any back fire now when I
accelerate.

 

If you set the CO to 3% and plug the 02 back in the system will fight to bring the car back to .5CO at idle. The end result is it can start to idle strange and have off throttle drivability issues. I always leave the 02 unplugged and allow the system to default to 45% duty.

I also leave the air injection unplugged. It just leans out the exhaust stream and creates heat..

 

Thanks Stephen !