No or low spark #4 and #7 plugs

[DTZ ZR1]

I have a 90 ZR-1 and I was having a problem with my engine running rough and also having SYS flash on my display. I changed the battery because I did have problems with it and that took care of the SYS. At first it seemed to clear the engine problem. Took the car on a 400 mile trip over the 4th, she performed flawlessly. This week she started to idle real rough and felt like a cylinder was miss firing. I changed the easiest thing the plugs, I put AC 41-602s in. I took 1,3,5, & 7 out and replaced them. I started the motor and it still was idling rough. I then took out 2,4,6, & 8, when I took #4 out it was wet. I replaced those four and started the motor. It idled better, but still not what I liked. I then took #4 wire off, idle did not change. Took all the other wires off, I could hear the spark jump and engine idled rougher except for #7, there was no change. I looked at my service manual and found that they are off the same coil pack so I figured that I would replace all four. The question is while I have the plenum off what else should I change or look at? Also is there anything I need to be aware of when removing it? What would be a good coil pack to replace them with? Thanks for the help.