Cylinder Firing issue

Hey All,

I am having an issue with my number 2 and 4 cylinder not firing, at first I thought it was a bad coil because I thought that 1/3 and 2/4 were on the same coils but I was wrong it is set up 1/4 and 2/3. Could it still be a coil issue or is it more likely something else? The most recent thing I did to the engine was replace all 4 spark plug caps because a few of them had cracked form old age maybe that has to do something with it? I am rather stumped any input is greatly appreciated...
Thanks in advance

Pull the plugs out and install them into the plug boots.
Lay the plugs against the engine and try cranking the motor over to see if youre getting spark.
If youre getting spark id move on to the carbs.
If youre not getting fire then id check the coils/wires.