My daughter’s 1999 SAAB 9-3 coupe tends to stall when idling. It only happens when it is warm. It will idle smoothly then it will stutter and stall without warning. The car also runs very poorly for a couple of minutes right after you fill the gas tank. I have changed the plugs, cleaned the idle control valve, change the PCV valve, changed all the vaccume lines and checked the evap purge valve and changed the fuel filter. It is still stalling. I’m out of ideas. Anything else i can try before I breakdown and take it to a dealer?
Sometimes cleaning an Idle Air valve does not help and they must be replaced.
Before going that far you might consider having AutoZone or Advance pull any codes that may be present and post any results back here.
The info on the car is a bit sparse, but offhand I might be leaning towards a vacuum leak, which could be anywhere.
The easiest way to determine a vacuum leak is to connect a vacuum gauge to the intake manifold.
If you don’t have a vacuum gauge (most people don’t) I would highly recommend one if you do a lot of that DIY stuff.
The gauges are cheap, easy to use, and can tell you a lot of things about an engine in a heartbeat.