Afternoon, experiencing a misfire on my Terios K3 EFI. OBD message P300 misfiring multiple cylinders. Then later P302 misfiring 2nd Cylinder. Changed all the spark plugs still same problem. Swapped pencil coil on cylinder 2 to cylinder 4 but no change swapped cyl 2 and cyl 1 pencil coil no change. Bought four new pencil coils and with four new ones the car does not even start AT ALL. Went back to old coils and car starts but still same misfire. So two questions. Possible causes of misfire and logical steps to take to eliminate until root cause found and 2 the only difference between old and new coils is that they do not earth through where they bolt down as they are painted and the old coils are bare and can earth, does the metal were they bolt down need to earth?