Ford Repair: EGR PROBLEMS, egr valve, dpfe

Question
2002 MUSTANG GT 4.6L V8. DID NOT GET A CHECK ENGINE LIGHT, BUT ACTED LIKE THE DPFE. JERKING UNDER NO LOAD ON MOTOR. CHANGED DPFE, CHANGED THE THE EGR CONTROLLER, AND CLEANED THE EGR VALVE. ( HARDLY EVER GO BAD JUST GETS CARBONED). VACUUMED TESTED EGR VALVE. IT TOOK LESS THAN 1hg TO OPEN EGR 100%. BAD EGR VALVE! REPLACED EGR VALVE. D D D. NO IMPROVEMENT. I'M AT A LOSS. ONCE I REMOVE THE THE VAC. LINE TO THE EGR VALVE; EVERYTHING IS PEACHY MINUS MY GAS MILEAGE.I COULDN'T HAVE BOUGHT 3 DEFECTIVE PARTS.

Answer
Three defective parts are unlikely,have seen it on carburetors.Have you changed the fuel filter?It gives those symptoms.I hardly ever will change a sensor without a code,but you may know something I don't.Another possibility,did you get some bad gas?Let me know back please.