oxygen sensor symptoms?

Hi ! i'm wundering what are the symptoms if the oxygen sensor goes bad my 96 grand am gt has 80 000 something km and i havent changed it yet.

It usually cause horrible gas mileage and eratic performance and idle when it goes into closed loop.

It usually cause horrible gas mileage and eratic performance and idle when it goes into closed loop.
hi! thanks for the response formulaLT1 i just changed my spark plugs,wires and gas ,air filter cause i noticed i have bad gas mileage but now that you told me this i think i'll go and change this sensor .Is it expensive ?is it something i can change myself or do i have to take it in and by the way where do you find the oxygen sensor on the car is it visible?

You can easily look up pricing on many site such as www.carparts.com (http://www.carparts.com) , www.autozone.com (http://www.autozone.com) . www.pepboys.com (http://www.pepboys.com) and there are many more. As for changing them it depends whiich engine you have how hard it is to get to but they are usually fairly easy. they can easily seen on the Exhaust manifold. You just unplug the harness clip and then use a open end wrench or special oxygen sensor socket(available at most auto parts store's) to unbolt the sensor and then bolt in the new sensor(make sure it has the anit seize compound on it,they usually come new with it on). Good Luck.
John

If your O2 sensor goes bad, chances are you will also have an erratic idle, loss of power, loss of mpg, and possibly a check engine light. If you are only seeing a loss in mpg, check tire pressure and fuel filter as well.

That is true tire pressure is normally something that is quickly overlooked when it comes to horrible MPG and OBD 2 systems are quick to set a trouble code for a oxygen sensor that operates out of normal range like most o2 sensor do when they need replacing but seeing as you replaced your fuel filter and if your tire pressure isn't out of tire specs. It very well could be a possible cause.