Spark issues on 91 Z24 HELLLP!!!

Hey i jus picked up a 91 z24 ran great when got it.... but as it has been driving for the last week it has started a sputter... upon this happening i check ouit the ignition an fuel system it turns out cylinder 5 and 2 werent firing... so i replaced the coils and the backing plate for it and tested all cylinders for spark again and it was fine... when i started up the car the next day the sputter was back... after checking it out i now wasnt firing on cylinders 1 and 4 ..... I dont know what this problem could be... I am goingto try replacing the backing plate for the coils... again and see if that helps but any input on this problem would be awesome

THANKS

After changing the backing plate to the modules no change im so confused

I assume you checked plugs and wires? These are a "waste spark" system, where both cylinders on each pack fire at the same time, so an open in either wire will cause a miss on both. You can also unplug both wires on a coil and the spark should jump the gap between the towers. Try that on your 1/4 coil pack, if you have spark there, your problem is in the plugs/wires