@
haute idle dip and partial stall / lights flicker was a problem I had when I had an ABS / CEL light for a broken ABS module, throwing me in limp mode.
This was on manual transmission though. Interesting that yours isn't throwing a CEL.
Maybe time for a diagnosis at the dealership! Also, try to get a video of the problem sometime, preferrably with somebody else filming while you're at the wheel.