2005 Taurus, O2 sensors
I'm diagnosing a friend's car that showed 6 codes related to the O2 sensors. 2 copies each of Bank 1/2 Sensor x Lean (don't recall if it's sensor 1 or 2, I neglected to write anything down) and 1 each for signal stuck.
I know how to test them, get them hot and put a voltmeter on them. But what reading should I get?
If the sensors are good, what else should I look at?
I can't imagine it's related but it also had two codes related to misfires (random-multiple and "in first 1000"). The car does run nice and smooth though.