Two things for the idle speed. Firstly, try cleaning out the idle control valve, I've copied the relevant section of this article: www.saabcentral.com/techhelp/c900/idling_problems.php <<< it describes lots of different checks you can make to get a Saab to idle nicely.
"4. Cleaning out the AIC
The AIC builds up all sorts of sticky black stuff inside, which stop it controlling properly. Remove the AIC valve and flush it out with carb cleaner, follow up the carb cleaner with WD40. You should remove a lot of sticky carbon deposits. On the Lucas equipped car take the AIC valve apart. The plastic actuator screws into the aluminium body with a very large hex nut but you can sometimes remove it with some long nosed pliers. There is a conical plug that moves in and out to control the idle - it is usually coked with hard deposits and you need some carb cleaner and an old toothbrush to shift it from all the moving surfaces. Some WD40 along the shaft towards the electric parts to finish off. To check Lucas AIC operation connect the plug up before putting the body back on - bung up the 2 throttle to AIC hoses and start the engine. It should idle low or stall with a warm engine and the hoses blocked - if not you have an air leak somewhere past the throttle plate. Also observe the conical plug as you increase and decrease the idle speed by opening and closing the blocked pipe on the inlet side of the throttle, it should move in and out in small steps as the ECU senses the wrong idle speed and tries to compensate. Don't vary engine speed by opening the throttle, as the ECU will only respond when it senses a shut throttle. If you get no movement from the conical plug your AIC may be faulty or you may have an ECU problem or the throttle position sensor may be wrong. Refit to the AIC body with the soft gasket and a dab of loctite on the threads."
Secondly, there was a technical service bulletin issued to Saab dealers explaining that there was some fundamental flaw in the Lucas control unit and that only units after a certain date code should be fitted to cars. The instructions to the Saab dealer were to remove the faulty units and replace with the later 'fixed' units. I wish I could find the info for you but I've no idea where I saw it. Hopefully cleaning the idle control valve will solve this.
There is another website for the MG RV8 which had the same system (as well as some Range Rovers and TVRs) which goes through in detail how the Lucas system operates. There will be some differences because this is in the context of a different vehicle so not identical to the Saab. Nonetheless, the article should be very useful to you. www.rv8r.co.uk/standardecu1.html
"4. Cleaning out the AIC
The AIC builds up all sorts of sticky black stuff inside, which stop it controlling properly. Remove the AIC valve and flush it out with carb cleaner, follow up the carb cleaner with WD40. You should remove a lot of sticky carbon deposits. On the Lucas equipped car take the AIC valve apart. The plastic actuator screws into the aluminium body with a very large hex nut but you can sometimes remove it with some long nosed pliers. There is a conical plug that moves in and out to control the idle - it is usually coked with hard deposits and you need some carb cleaner and an old toothbrush to shift it from all the moving surfaces. Some WD40 along the shaft towards the electric parts to finish off. To check Lucas AIC operation connect the plug up before putting the body back on - bung up the 2 throttle to AIC hoses and start the engine. It should idle low or stall with a warm engine and the hoses blocked - if not you have an air leak somewhere past the throttle plate. Also observe the conical plug as you increase and decrease the idle speed by opening and closing the blocked pipe on the inlet side of the throttle, it should move in and out in small steps as the ECU senses the wrong idle speed and tries to compensate. Don't vary engine speed by opening the throttle, as the ECU will only respond when it senses a shut throttle. If you get no movement from the conical plug your AIC may be faulty or you may have an ECU problem or the throttle position sensor may be wrong. Refit to the AIC body with the soft gasket and a dab of loctite on the threads."
Secondly, there was a technical service bulletin issued to Saab dealers explaining that there was some fundamental flaw in the Lucas control unit and that only units after a certain date code should be fitted to cars. The instructions to the Saab dealer were to remove the faulty units and replace with the later 'fixed' units. I wish I could find the info for you but I've no idea where I saw it. Hopefully cleaning the idle control valve will solve this.
There is another website for the MG RV8 which had the same system (as well as some Range Rovers and TVRs) which goes through in detail how the Lucas system operates. There will be some differences because this is in the context of a different vehicle so not identical to the Saab. Nonetheless, the article should be very useful to you. www.rv8r.co.uk/standardecu1.html