My 95 3.1L Lumina has 266,666 miles and for a long time the SES light comes on and stays on when I go down this one particular hill each morning. It started misfiring pretty bad the other day with the Low Coolant light coming on even with a full radiator. I changed the plugs and it ran good for a day or two but developed a bad sputter that will not go away plus it has a real bad odor like methane or sulphur. All the plug boots are on OK. I suspect a bad O2 sensor but don't want to spend $90 and that not be it. It does not have the B wire on the OBD so I can't get codes. I've had the car 2 years and other than a water pump have had no problems. Any thoughts?

As I have been informed that the auto parts houses cannot scan OBD I systems you should take it to a reputable shop and have them scan it and either post the results,( In Detail), here or have them fix it. There is no sense in throwing parts at a problem. As a rule you will end up with a poor batting average.

Amen to that!!!!!!!!!! discnik