I think the Cold Start Valve (an extra injector) was used on the earlier 900’s and not yours…I still havent confirmed this yet.
I would do the following…
Look carefully for vacume leaks and or broken vac hoses
Clean your MAF sensor heres a link for it…http://pages.infinit.net/mlbriand/saab/iac/page1.html
It also wouldnt hurt you to clean out your AIC valve…this is a very common issue on the 900…it controls your idle by a controlled vacume leak…it is temperature controlled and over time they get clogged up with carbon…By far one of the most attention getting (I should say neglected) parts on the 900…if you havent cleaned it or never heard of it…look it up.
Make sure your Air filter is clean…
How is your fuel filter? Also your fuel pressure regulator…check that vac line as well…
Aside from that its been a long time since I turned wrenches on my Saabs…I’d have to have the car in front of me to rapid fire check all the things that come to mind.
Lastly…GO HERE… WWW.SAABNET.COM… TONS O Saab info …and SAAB STORIES…lol
If you cant find help there you cant be helped…they have seen your issue before and fixed…many X over…great people too. That website is invaluable to ANY Saab owner and really a MUST HAVE for anyone owning a Saab. CHECK IT OUT FOR CERTAIN