where is the evap pressure sensor and the evap purge valve
fault code according to autozone code reader /evap canister purge valve mechanical fault orVMV default condition
as far as i can rember their is no sensor or purge valve,it is just plastic lines on it,may be cloged up or one of the lines has broken,autozone scans dont really tell whats wrong,just possable bad things,ask them for a printout of their scan,it will have a list of possable things that could be causeing your problem.
The evap purge valve is below the air-cleaner on a 1997 escort.
Here's a pic of the evap system