does not having the secondary o2 plugged in affect any kind of performance? i've gotten both answers from different people and i still dont know the right answer.

 

The short answer is that the sole purpose of the secondary O2 sensor is to monitor whether the catalytic converter is functional (emissions). Without this sensor, however, your catalytic converter could get clogged without your knowledge, and this condition would lower performance.

 

What if you have removed the cat? Any performance issues or other problems with not having the second o2 hooked up?