My car runs great 175k on it I have NEVER chgd the 02 sensor and the guy at the Pontiac dealer that I ask for tech advise when I can't figure out something said "as long as the chek engine light is not on leave it alone" I have seen others here say to chg anyway, whats the deal ?

How has your milage been?? If it really sucks,change it!!!!

O2 sensors rarely throw a code and a light. They'll run weak for years in this mode. Most are tired after 60k.

I guess that decision would be up to you? It depends on the price of the 02 sensor. If the 02 sensor is like 20 bucks, go ahead and change it. It will probably improve your gas milage quite a bit!

i have a 97 SSE, and i changed mine for the first time at 115,000 miles. there was no check engine light on when i changed it. Its been changed for about a month now, and i have experienced exceptional gas mileage gains. before i changed it, i was averaging aroud 17mpg, and now im around 22-23 mpg.

If you believe it will help. Most see an increase in mileage of 2-3 mpg when they do it.

Just changed it, 175k miles and it looked kinda tan colored with slots in it and stamped AC, I bought a Denso at local auto store 50.00 with tax. I just sprayed it with Kroil while still fairly warm and took a 7/8" openend and it broke right loose. Turned out to ba about a 15 minute job. I am anxious to see if my mileage goes up but I guess its a done deal now anyway. I noticed my brake lines were looking a little rusty so I sprayed them up with wire rope lube. This stuff is great it a black sticky mess but penetrates the metal and lasts a long time. Oh well should have over 200k on it by next year at this time unless someone offers me a nice price then Ill buy a Park Ave ! (used)