I heard many people like to change O2 sensor if check engine light was on. It sounds like the only reason? No, You will find CEL come back after you do that, also an O2 sensor is expensive. Try to diagnose the car before you do something.
车上“CHECK ENGINE” 的黄灯亮了，还差十天换机油(上次换后跑了4000KM，2个多月)，会不会是该提前换油，不过开车没感觉异样，可千万别有什么大的隐患。各位DX有无类似经验，多谢！！！