Thanks for all input vs my idling problem.

It seems that the problem was -as usual- not so very exotic as my brain
tried to make it. I took apart and sprayed all connectors relating to the
engine, even on a black box in a socket "behind" the right rear light, that
I had to remove.

Then surprise! a nice and stable idle at all engine temperatures.

Johan Nyberg, Sodertalje Sweden
'86 Caravelle C
'62 Wife
'85 Daughter
'87 Son
'88 Son
'91 Son
'93 Daughter

(Signature concept gratefully stolen from Tim Casey)