Hello , thanks for your question in the autoaid Community.
Your described fault Code means: misfire under cylinder 3
Check your spark plugs and change these with the other cylinders for test if the fault goes to another cylinder.
If this went to another cylinder, then Change your Sparks complete.
Use original Ford (Motorcraft) Spark Plugs, other Spark Plugs working not correktly..
You have renewed complete coil pack, or only the cables? Or have this engine single spark Coils?
Another Problem could come from the air mass meter, or the ecu.. but these things are very rare..