Adding this info from another thread so that Wideband O2 stays up to date.
Below is a chart of a startup sequence and drive off. You can see the richness starting on the left, moving to closed loop at 14.2:1 AFR on the right. In between are some lean splikes from deceleration enleanment and from fuel overrun cuttoff (biggest splikes). You can also see a restart just right of center where it goes quickly through a rich sequence (idle lever not up). You can also see some rich blips as I roll the throttle on.