I have a 2000 Dodge neon that the light on the dash has come on telling me that their is somthing wroung with the O2 sensor. I see that the car has two of them does any one know which one might be bad or should I put two new ones in? Please help!
The downstream O2 sensor is usually the first one to go. Get the car up on a lift or jack it up. the sensor is easy to reach if your under the car. I can't remember if it is a 13/16 wrench but anyway pull the sensor and take a look at the thing. chances are if it has a lot of debris on it it's shot if it's clean then it's probably good and you need to change the other sensor at the manifold.