My check engine light suddenly lit up today and I had the car serviced. It looks like the O2 sensor under the car is going bad or loose. The front one on the air intake is doing good. The part O2 part itself cost $88.57 and labor is $40., totalling $130. I hear that the air in the atmosphere affects the O2 sensor. Should I wait it off a week to see if the check engine light goes off or get it replaced? Need sugguestions.