Knock Sensor and O2 Sensor Malfunction?
I need a little help here because I am very confused and need help picking a starting point. I have a 2008 cobalt ls, 2.2L 5 speed. I have had this car since 2008, it is my first car, she just turned 100k miles last year, and she is my baby! The last three years I have been storing her for winter, I live in NY and winters are rough on cars here. I finally got a big boy job and decided to spend a little money on the blue beauty. I bought a Magnaflow catback exhaust for her, and the install went on without a hitch. About a week after doing the install, a check engine light came on, something this car has never done to me in 10 years. I plugged in a code reader and got knock sensor circuit low, downstream o2 sensor lean, and downstream o2 sensor rich. I did what Magnaflow said and disconnected the battery after the install to reset the computer, but it is still giving me a light, and I can smell gas from the exhaust now, another thing this car has never done. My point of confusion is, did something go wrong with a sensor while it was in storage? The car is getting older and it may be a coincidence considering I've done catbacks on other vehicles before and have had no problems. Could a knock sensor cause the o2 sensor to mess up? Can the o2 sensor cause the knock sensor to malfunction? Did both sensors go bad because they are old? Did putting a catback on it cause an issue? I'm reaching out for a little help here. It runs and drives fine, no new noises (other than the exhaust, which sounds sweet!). I'm just confused, any advise would be much appreciated. Thank you for taking the time to read this!