Error code: Bank 1 too lean.
 

My dash display recently alerted me that "service emissions system soon." I went to the parts store and borrowed their OBD reader and the codes that popped up was.
"Bank 1 too lean and Bank 2 too lean" Does anyone know what this means? O2 sensors? Any input will help!

Any recent changes or other repairs? To have both sensors to fail simultaneously would be rare. Recent long winter storage? Open up the ranch and look for rodent damage to intake hose or vacuum lines.

I got that when I went for the airbox delete. Appeared twice but after a bit it seems the ECU learned and the fault didn't return any more.