I've got a vehicle that is running less than one tenth of a volt on O2 sensor...I can trick vehicle to run rich at 0.9 volt.
This is a 1984 Bosch LH II system, which currently is only using the Air Mass Meter (Mass Air Flow) to determine fuel amount.
At this time, I have concluded the ECU (ECM) is messed up.
Question - It drives OK....no higher RPM misses...just smooth driving. At idle, its a pinch rough.....should I fix it?
Water temp is OK....