what is vapor locking on a 2000 lincoln navigator and how do you stop it

Vapor lock is a condition in vintage cars where the gasoline in the carburetor and fuel pump vaporizes and the pump is unable to overcome the situation resulting in stalling.

A 2000 Navigator has a modern high-pressure fuel injection system that basically cannot vapor lock.

Vapor locking is caused by fuel boiling in the fuel rails, although it is unusual on a modern EF l vehicle it will still happen occasionally if you are operating the vehicle in an extremely hot climate. There is not a lot that you can do about it unfortunately, try to avoid idle time and slow driving if possible and also if you are using gas with ethanol mixed in it try using regular unleaded fuel when it is hot out, the alcohol boils at a lower temperature then gas does.