What can I do to fix a misfire on 1999 Ford Expedition

Vehicle didn't have a misfire just a bad coil in #8, so I decided to replace all Spark Plugs and Coils, Trottle position sensor,EGR pressure Feedback sensor,EGR valve,Idle Control valve after all this was done I got codes P0353 and P0356, checked connecters and rechecked spark plugs and also changed out coils 3-6 but Notting what can I Do now

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1 answer 2 comments
MOTORCRAFT PARTS???? Hard to beat FoMoCo parts on a Ford vehicle, especially electronics!
Yes all......parts
So much for that! Possible ecm but not likely. There has got be a circuit problem to 3 & 6. Check connectors with dvom and compare to working cylinder. Are those two cyls. misfiring so as you can tell it with engine idling?
Maybe take it to a mechanic!