O2 sensors at WOT?

[Orin Eman]

> I had always heard, but never tested, that the O2 sensor reads *lean*
> under conditions of a rich misfire, due to lots of O2 in the exhaust.
> Sounds like this would be an easy test to see if the O2 sensor is
> really responding to O2 or HC. Comments? Maybe I need to go yank off
> a plug wire...

Absolutely.  An ignition miss will force the mixture rich and
can foul up the plugs mighty fast.

The O2 sensor really is reacting to oxygen... misfire means
lots of oxygen left along with unburnt fuel, but the sensor
doesn't care about the fuel and signals lean.

Orin.