well i replaced the headers and exhaust and cat in my 98 civic. a few weeks later the check engine lights came on. i think my 02 sensor went bad. after i have the codes checked i will know for sure, but assuming they did go bad can i just use 02 bypass sensor to insure my car is running correctly. not sure what to do please let me know! thats for the help

 

i think you're thinking of a o2 simulator, but the only thing it does is trick your car that it's operating correctly when its not. it gets rid of the CEL, but really, your exhaust sys. might have a prob