The check engine soon light came on the other day. The car seems to run fine. I changed the oil and filter yesterday and put in a fresh tank of gas and it is still on which doesn't surprise me. I read if your gas cap isn't on tight it will mess with the electronics somehow. Or if you get some bad gas or run the tank fairly low which I did but there was at least 1/8 of a tank in it when I filled it back up. I did put on a locking gas cap but that isn't the problem I am thinking. The PO replaced the PCV valve at 121k. The car now has 158k. Air filter was replaced at 92k. I guess I can replace that. Other than that does anybody have any ideas?