Subaru Outback dying on stop

My Subaru 2000 Outback is dying occasionally when I come to a stop. It will stutter and die. I can restart it and everything is fine. It does not happen everytime, but happens more when I come to stop quickly, less when I come to a gradual stop. What is this?

This usually points to a problem with the Idle Air Valve or it’s circuitry although there’s always the possibility of a vacuum leak. My opinion is that an engine should always be checked for a vacum leak, or anomaly, as a first step because it is so quick and easy to do.
If it’s the IAC, sometimes cleaning the valve and passages may help. (If you’ve heard about “induction service” then that would include this particular chore.

Finding a mechanic who uses a vacuum gauge and knows how to interpret it may not be as easy. Hope that helps.

Cleaning the EGR vavle may help also.

If you have a vacuum leak, engine speed or the way the car runs is definitely affected. The car may be adjusting for it so you may not notice the stumble at idle - that makes it hard to find.
You can often detect it by shooting a little starter fluid (=ether) around suspected areas with the car running. If the engine speed is briefly affected, you’re on the right track.