Oxygen Sensor

My 1998 Lumina LTZ with 3.8L is running well. I have 106,000 miles on it. Do I need to change the Oxygen Sensors? Plugs were changed at 100,000K

I replaced mine at the same poiint, just for the hell of it. I figured it couldnt hurt anything, and will prob get a little better gas mileage. If you do change it, buy the socket that fits the Sensor. (it has a notch cut in the side of the socket) Makes it alot easier.

Couldn't hurt, might help. Gas prices what they are, I can use all the help I can get. They get slow with age.

If the Oxygen Sensor gets slow with old age (135,000 miles), can that cause significant gas mileage drops as noted in the post? Will the exhaust start to get carbony (new word)? Will there be a reduction in engine performance as felt in the seat of the pants?

You wont be able to feel a slow sensor, but your cars computer and your wallet might. Most OBD II cars PCMs will pick up on a slow sensor if its really bad. If its just a bit sluggish, the PCM wont turn on a light but your fuel mileage might suffer. Bosch recomends replacing O2 sensors every 50,000 miles. A marketing gimmick? Maybe, but its not gonna hurt anything.