engine speed and AT

[Snoopy]

Hi. Does my car have any kind of engine speed increase/regulation,
when the car is not moving, transmission is in "D", and brakes are applied?

Recently I noticed a very slight engine "shake" under conditions
mentioned above. It can be increased for example by pushing window
button, then engine visibly drops ~100rpm and starts shaking like it
was working on 4 cylinders. Normal idle (transmission in P or N) is
fine.


Audi 100 '90 2.3 NF
4spd AEK automatic tranny


-- 
   Snoopy
\/noway.lt/\