1995 Mercury Grand Marquis mileage: 75,000. Check engine light code 332? The EGR valve not opening. I had this problem on another Mercury Marquis and dealer cleaned EGR with spray without removing and changed vacuum regulator. How can I tell if it is the vacuum regulator or carbon blocking the EGR valve?
The EGR valve is controlled by the vacuum control motor. Check the EGR valve to see if it is plugged by manually raising the EGR valve with the engine idling. If it is not plugged, raising the valve should almost kill the engine.