1987 190e 2.6 110k

The O2 sensor light has been coming on causing the car to run rough/stumble/stall etc. I replaced the sensor at about 90K (the one in the top of the exhaust pipe forward of the Catalytic Convertor). Seems to me that this shouldn't be failing again this soon. It was suggested that perhaps the convertor is failing and backing up exhaust gasses that fool the sensor. Does this make sense? What else could be wrong. Seems to cure itself if I let the car sit but it will repeat itself within 2-3 days. It is most uncomfortable when it happens on the freeway at 65!

Any suggestions or thoughts would be appreciated.

Pat..

Check that the o2 sensor
wiring is not grounded.(or grounding)

Clauser1