92 Runs great till punched, Please help....

[4x4 TC]

I have a 92 TC, recently it begain to run rough cut out pop and hiss when you put a load on it, but fine when ideling. I've openned up the exhaust and changed the fuel filter but notta. The check engine light revealed the EGR valve opening was not detected but a machanic here in town said after supposedly checking it out for me that he thought something else was wrong. SO PLEASE HELP ME.......... PS The Lincoln only has 100,000 miles and the 4.6.

[Towncar]

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