Well, my '97 Deville - with just 104K having rolled under her flanks - is displaying a symptom I haven't heard or seen on this board before: Sometimes (and only sometimes) while doing my weekly WOTS, her "service engine soon (SES)" light will go on and the car will shift harder, until she is turned off. Once she's turned back on the light is off and the shifts are back being their same old, buttery smooth selves.
So, what gives? Anyone else had this happen with WOTS (hard shifting right afterwards and the SES light coming on)? Only to have all symptoms disappear the next time I crank the motor?
I'd check for codes, but can't do it thru the climate control anymore - problem with the "warm" button!