So I Decided to take my car into autozone today because 1 it sometimes takes a minute to start.. but other times it starts right away.. also recently if it starts up right away it high idles between 1.5 to 2.5k then after a couple minutes it settles down.. then.. I was having issues with it idling so low the car would die.. anyways.. I had the same reads before maint was performed to it.. and a valve adjust was done and they swapped all 4 spark plugs and reset the ECU everything was fine car was driving good again.. and then after 3 or 4 times out.. it CEL again Read the ECU fault codes are P0300, P0301,P0302, P0303,P0304, and P0420 Could a faulty C2 sensor be the root of all the problems bc the ECU is trying to correct it all the conditions I have are intermittent sometimes the car runs amazingly well..