Does anyone know what a purge flow sensor valve is? thanks

 

http://www.asashop.org/autoinc/march2002/techtips.cfm

 

Thank you for that shortcut, i have a friend that I work with that has a mercury tracer and her mechanic said that her purge flow sensor is bad and it will be like $250 to fix it. Is this an easy fix? Sorry this isn't about mustangs, but I figured i would get a faster reponse on here than googling the question.

 

It should be located on the opposite end of the intake from the throttle body.