PLEASE HELP.

1986 560SEL W126 Vehicle developed stalling problem. Drives perfectly but intermittently loses power and stalls. RPMs drop way down. Gassing has no effect. Highly dangerous and could be a road rage inciter.

Replaced fuel filter with no change. Then disconnected the oxygen sensor in the RH footwell. Installed voltmeter between signal wire from the O2 sensor and ground. Grounded the signal wire going to the injector computer module. Car now drives in open loop (since O2 sensor input is grounded) without any problem and I am monitoring the output voltage from the O2 sensor. Believe it or not the voltage ranges between -0.1 (lean) and -0.9 (rich).

NO....the leads are not reversed on the meter. Trust me on this.

I have NEVER heard of an O2 sensor outputting the correct range but with negative polarity or even with neg polarity period.

Can anyone here enlighten me as to what is going on. I will in time change out the sensor to see if it has been poisoned or has otherwise failed. The sensor heater is working to spec.

The sensor has only 5000 miles on it although my Bosch time warranty has expired timewise.

Engine emissions and condition are all to specification.

PLEASE HELP.

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Dionysius