Outer Limits 4x4 Board

My 97 TJ Wrangler has been running rough since I got my extractors replaced, I disconnect the sensor coming from the bottom of the extractors and all is good now it would seem, any ideas what this is for and do I need to replace it or just leave it unplugged???

O2 sensor - yup you need it - so if it's running crappo it's prob time to get a newbie.....
Also on your 97 you can run your error coded to help isolate it