IF (big IF) the sensors are reliable, AND the engine is running properly, lean means lean.does the LEAN indicator in the EngineData mean it's running lean?
If not, then what's the purpose for it?
As I've said multiple times, misfire creates a situation where the O2 sensors report FALSE lean, and disconnecting them entirely means the computer is not getting proper signal from the sensors, so it has no idea what's going on. The total lack of sensor voltage would indicate extreme leanness.
IF things were working right, the O2 sensors would correctly report the oxygen content of the exhaust, which is ASSUMED to measure the quality of combustion--rich or lean varies the exhaust oxygen. However, it's an OXYGEN sensor not a carbon monoxide sensor or a hydrocarbon sensor. It does not measure mixture strength directly.