how do u know when an o2 sensor is bad? Options

[xs94st]

yea..i get really bad fuel economy. lookin at 20-25 mpg. i know i drive at about 75-80 on the freeway, but i didnt think that it would reduce my mpg by that much..plus i see that it goes down alot when im driving regularly..

just maybe running to rich..maybe reset ecu? but main question is how do you know if your o2 sensor is bad.

thanks guys!

x

[1bwilson]

Ive never had one go bad before but when I removed one I know it almost instantly flipped a CEL s Id assume it would do the same if one dies. Odd thing for me is I just unhooked the batt and the CEL went away and never came back.

[vile_v]

Ive never had one go bad before but when I removed one I know it almost instantly flipped a CEL s Id assume it would do the same if one dies. Odd thing for me is I just unhooked the batt and the CEL went away and never came back.

just adding on the what 1bwilson said. There is a good possiblility that its your o2 sensor when your cel light randomly comes on and than when you restart the engine it goes off and comes on again.

Another good way to tell if your running rich is to take out your sparkplugs, if its all black your running rich. Good possiblilty that your o2 is not working properly. Hope that helps you out.