O2 sensor stuck lean

Why could it not be an 02 sensor? If the value isn't changing continuously then the sensor or wiring is bad.
You should be able to look up in you owners manual how often that sensor is to be changed. Some were 30 or 60K.

roadrat57 wrote:
Hi!
I own a 2008 Ford V-10 that trips the check engine light at idle - bank 1 sensor 1 stuck lean.
Two possible causes, vacuum leak or mass air flow sensor. I think.

Bad sensor ?

More likely vacuum leak.