Stalling is generally caused by Vacuum leaks. Check all vacuum hoses thoroughly. Vacuum hose wear can generally be identified by noting that the ends of the hoses tend to crack. On Turbo models a major problem area is the Turbo-Bypass valve. The diaphragm in the Bypass valve develops a hole and can often create stalling problems!
Thanks to Rick Blake for contributing to this FAQ!
900 NG, stalling at idle, usually about 30-60 seconds after coming to a stop can be caused by a defective charcoal/vapor recovery canister in the fuel system. A defective canister can cause fuel pressure to drop momentarily. The ECU can interpret this as a fuel leak, and Saab engineering treated this as a potential safety hazard (broken line, etc). ECU programming kicks in and stops the engine to prevent fire etc.
This was found by another Saabsite member, I believe, and when my wife's 1998 900 Turbo Conv. started doing this, it took two weeks and a DIC before the dealer tech heard my advice 'from the Internet', worked through the logic, and tried a 'spare' used canister he had around. Bingo! We put in a new one of course.
One other issue that can cause stalling is a dirty throttlebody. In general, the gap between throttle plate and the throttle body itself should be around 2 thousands but when carbon build up closes that gap the car will begin to stall when coming to a stop because the engine can no longer breath.
Thanks to Martin Leavy for contributing to this FAQ!
I had this problem,car would stall when slowing down to stop or even slowing down to about 30k's to turn a corner!! dealer took a few tries, checking for air leaks etc before he changed a crankshaft sensor which sorted the problem.
Thanks to Eric Ford for contributing to this FAQ!
A faulty purge valve caused my 98 900SE turbo to stall or bog down at stops. Took numerous mechanics and many check engine lights to track down this cause. It is closely related to the charcoal canister mentioned in a previous tip. It now idles flawlessly without any anomalies.
Jeff Cook Contribution: Wow......this really saved my sanity. My 1998 900SE turbo was stalling about 30s to 1min after coming to a stop. When accelerating and driving there was no problem. I took it to three mechanics and they could find nothing wrong with it. One of them was even a self-proclaimed "Saab only" mechanic. I realized the problem was worse right after filling up the gas tank--and apparently this is consistent with EVAP purge valve issues. I
popped in the $50 part the next day, and the idle is now flawless.