HI, my car is showing the hard codes 223 & 224 (failure on primary system coil, on coils 1,2,3 or 4)during the KOER, but i don't know what is the primary or the secondary system coil, due to my car Ranger 2.3l EDIs have a pair of coils, would you help me what i should i do or check to correct this problem?:mind-blow

Test the coils. Simple enough.

Or at least be sure the harness is plugged into them. I have pulled a 224 after getting AC work done, because the plug got pulled off getting the AC clutch or some other jazz out of the way.

Tachometer idle reading = 400 RPMs = not good.