Victim:  2001 Ford Windstar 3.8
Capture:  All four O2 sensors
Scope:  Pico 3423 on a USB 1.1 PC
Method:  Filtered Save On Trigger Session @32k samples per channel
Conditions:  From start idling ending with a throttle snap

Here is the series:

Hi Carl,

Yes, it's triggering off of invisible noise.  The low pass filter has cleaned it up quite nicely.

The engine was not stone cold, but had been sitting for a while before this start up.  The O2s wake up very fast and are in closed loop in about 10 seconds.

BTW, the PCM was the test point.  Accessing the O2 connectors on this would be a nightmare.