what does a bad o2 senor act like and how to tell

[doc1281]

hi all can any one tell me what a bad o2 senor does and how to tell if it is bad
thank you

[2.link]

CEL

[FruityOne]

usually it throws a CEL...if not you get crappy gas mileage and your exhaust has a stronger smell of gas to it

[okczy21]

i get crappy gas mileage anyways like 18-20 in my 325is

[97alpineM3]

One of the key signs your gonna see if you drop a O2 sensor.. would have to be a very very rough idle.. and horrible gas mileage...

Les

[chungaa1]

any associated check engine light? cruise control not working? fuel running rich?
laters,
eric

[BMWBeauty416]

Originally posted by okczy21@Aug 29 2004, 10:18 PM
i get crappy gas mileage anyways like 18-20 in my 325is

wow do you know why it's so low? 2 comments on that I know I have a 4 banger but I get like 26-28 and I drive it hard, and if you thinks thats really bad I drove a '96 Land Rover Discovery all time 4 wheel drive just a huge a$s box it got 12 MILES TO THE GALLON! 12!!!

~*Teg*~

[97alpineM3]

Ok yes.. you will .. or should (if its working right) get a check engine light when your O2 sensor fails... gas mileage.. and just a rather bumpy idle... are some other problems you get when you lose a O2 sensor

les