I have a 2005 mercury montego i was sitting in patk idiling an the car shut off

Hello, it's difficult to say if you have an electrical power issue, such as from a dead vehicle battery possibly caused by a charging system issue, or an engine performance issue that has caused the stall. Hands on inspection and diagnostic testing will be needed to find out what is going on, unfortunately. Good luck.

This EXACT thing happened to me just last week while stuck in traffic on the 405 bypass through Seattle. Had it towed to the shop and (this will sound silly, but I kid you not) all it was was a blown fuse. I don't know which one, but I do know it was under the dashboard rather than under the hood. The behavior was precisely as you described.