Spark issues on 91 Z24 HELLLP!!!

[91ZZER]

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

[91ZZER]

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

[J-Ri]

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