I have a couple times, and i'm still not getting all of it. I've learned a bunch. On page 14, it says "Problem: The idle will oscillate between 1400 and 1600RPM in cold weather for a few seconds
after start up.
Solution: When the car is first started, Z19 raises the idle speed to keep the engine running.
If the value of Z19 is set too high the engine will run into deceleration fuel cutoff, at 1500 RPM,
that shuts the fuel injectors off. Lower Z19 by one point at a time until the oscillating stops. Z19
must be set higher than or equal to Z18; we recommend higher by 4 points."
Mine does it while its idling after its been heated up.