My car has high idle 1/min

Hello!
I think the engine of my car has high idle 1/min. In position D they are 900-930 1/min, in position N they are 840-870 1/min.
What should be the idle engine speed 1/min, in N and D position of the gearbox?
SAAB 9-5, MY 1998, 2.0t, 4 speed automatic transmission.
Thank you in advance for your answers!
BOBI

The WIS mentions an idle speed of 825 rpm but not many more details. There was an issue with engine vibration at lower idle rpms and dealers were advised to increase the idle speed. Here is the TSB: http://saabworld.net/showthread.php?t=1315