I think I should replace mine.. probably never been replaced @180k mi. But, MY car seems to run a bit rich (exhaust always smells bad- not like gas, but like very bad exhaust) - would replacing the O2 senson possibly help with the air/fuel mixture, or is it likely that if I replace it, the new o2 sensor can be ruined by the bad mixture?

Also, will an autozone one be just as good as getting one from the dealer?

 

Well, even thought you have that many miles on the car, it doesn't mean that that O2 sensor needs to be replaced. Replacing the O2 sensor will make the mixture more even...if the O2 sensor is the reason for it running rich, for instance if it were bad. If the rich condition is cause by something else, say a leaky injector or malfunctioning MAF, then a new O2 sensor will only be tellin the comp that its rich, but wit the O2 sensor not being the problem, the comp wont be able to do anything to correct it. Things like silicone gasket materials, if passed through the combustion chamber and burnt, will coat and cause the O2 sensor to fail, and I'm pretty sure that things like too much oil or coolant being burnt, and even too rich a mixture may harm it also.

Also if your exhaust is running rich than it would smell like gas, the really bad exhaust smell could be other things, you do have 180k on the motor. I might try Seafoam or Run Rite or something like that and see how that works first before I would go and start reaplcin parts.

 

Buy it from the dealer. Also, if you have broken exhaust manifold studs (*tick tick tick* when you accelerate), which is a common problem on your engine, that will cause your car to run rich and confuse the o2 sensor.

 

Sure, buy it from a dealer if you want to pay 2-3 times what it is worth. PM Internetautomar, he has them.

 

if you are already running rich you will / are killing your o2 as well as your cat.
I don't believe that autozone has the correct o2 for our cars even.
HOWEVER, I do

 

a chip will kill it all day long and screw up your combustion chamber