I have an 01 civic dx.Yesterday i installed new headers. I drove the car around and everything was fine. Then today as i was getting on the freeway, my CEL came on and is still on. Im pretty sure that it is because i dont have a catalytic converter anymore. The headers came with a plug foran o2 sensor. I just put both o2 sensors in anyways. My friend told me that the CEL came on cause of emmisions. If I just plug the second o2 sensor, will the CEL turn off? or does this have nothing to do with emmisions and i could be looking at a bigger problem??

 

pull the CEL code and make sure it's a O2 sensor error code. You should have re-installed both O2 sensors.

 

I believe that Auto Zone will tell you the error code for free. But i want to know if i can fix it myself before going there. Also, is it true that your car performs worse when the CEL is on?

 

well, depends, you should never ignore a CEL. If the CEL is because it isn't reading a O2 level, then the car will assume a default level and run from that. So it could run very bad. Just go to Autozone, why waste time? Just get the code and go from there.