EGR Valve problem

Hi, since we changed both head gasket on my Aerostar 97 the Engine light went on and the car was missing between 30 and 40 mph so I unpluged the vacuum on the EGR valve and runs ok so I changed the EGR and they are pretty expensive but did not fix the problem so I disconnected the electric swithc where the EGR vacuum goes and it's ok now but the engine light is on for shure so do I have to change this electric switch.Thank you

Generally the Differential Pressure feedback EGR sensor is the problem. Make sure the opening to the egr inlet is open they some times get clogged and make sure the hose is good before changing.