O2 Sensors and my check engine light
So I recently purchased a 97 Grand Cherokee Laredo under book price which needed some mechanical work. As we are getting into the vehicle, I checked the codes and it was due to O2 sensors, so I crawled under to check it out. The previous owner had replaced the exhaust with one that does not have a catalytic converter and no spot for the post-cat O2 sensor so the wiring is just zip tied up in there. Also the pre-cat sensor is in, but it was disconnected. I know that with them disconnected it will just default to a set fuel ratio, but I was wondering if I should hook up the pre-cat sensor and make a way to install the second sensor? I want to get good mileage and be nice to the engine, but without the cat. conv. I didn't know how that would affect the readings.