bad o2?

can an o2 sensor go bad and still work, or do they just work or dont? my gauge says im lean all the time no matter what rpm im at im running like 15 psi all stock 2 gen talon. is this fine to drive? what should all be checked?

check the gauge wiring

The sensor will fail gradually, not a good/no good type sensor ;) They will start to get lazy, and always read on the low side. If its not cycling at idle and light cruise, it needs to be replaced. If it doesnt come up to the normal area at WOT, then it is pretty far gone. Does it come up even a little at Wide Open Throttle? IF it stays on the same LED the whole time, then I Would suspect the gauge or its wiring as mnetioned above.

ok well im going to try a diffrent gauge tonight i know its wired corect. thanks

Well lets not say that it may be wired "incorrectly," since it once worked and I'm sure you know what you are doing. I was refering more to a problem that may have come up, bad connection, etc.