O2 sensor oscillations

[Greg Hermann]

>OK, Here's a question:
> I read that, while in closed loop - the voltage on the O2 sensor is
>supposed to cross 0.45 at some particular rate.
>
> Are these crossings producted by "puffs" of exhaust going across, or is
>the ECU intentionally running lean-rich-lean-rich-lean in order to keep
>the avg mix (over time) "centered" on the ideal?
>
>Thanks!
>-Bill
>
>I dunno, but some time with a scope hooked up to look at the frequency of
>the crossovers vs ignition spark frequency might well begin to give an
>answer--anybody???

Regards, Greg