O2 sensor symptoms?

[Dan Sinclair]

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Hi all,

While on the topic of 02 Sensors, what are some of the symptoms of 02 sensor
failure?

As some of you are aware, my CQ 20v is that one that's stalling.  I'm quite
sure the 02 sensor is original, and the car just turned 100,000 miles.  A
couple months ago, it started smelling of sulfur, but my mechanic didn't
think an O2 sensor was called for - I asked...  This weekend, however, after
all the stalling, surging, and carbon fouled plugs etc., I seem to think it
might be worth changing just for good measure.  O2 sensors regulate fuel/air
mix correct?  So could/would a failing sensor contribute to a rich mix,
carboned spark plugs or the sulfur stink?

Thanks,

Dan
1990 CQ