How do you determine if an O2 sensor (the ones in the exhaust) is bad other than going thru emissions and failing...

 

It should throw a CEL when it goes bad, then a quick plugin of an ODBII scanner can tell you usually if it's the O2 sensor and which one.

The other way is your mileage usually will drop quite a bit..

I've usually gotten about 80k miles on o2 sensors in all my other cars before they go.. and even then it's often just a ground issue.

 

Aaron,

My car has no cat, so the CEL is on all the time with codes in regards to the 02 sensor. As far as mileage dropping, that's due to the added power I just added LOL.

Is there any way to bench test one?

 

bump...