EGR Backpressure Transducer Valve
WARNING: This page is about a different car, the 1996 Mercury Villager and 1995 Mercury Villager. However, it is still accessible from the selected car via links, so may be relevant.
Locate EGR backpressure transducer valve between EGR valve and EGRC solenoid. Remove vacuum hoses from valve. Apply very light air pressure to bottom port of valve. If air flows freely, replace valve. If air does not flow freely, valve is okay.