Need an oracle! Low speed miss on cylinder #1 only.

[bmarcum]

Okay sorry for the lengthy post but I need some help. I have a LT5 shop manual but I can?t find it at the moment. I have a 1990 ZR-1 #103. The Z has about 109K miles on it at the moment. This is my second Z and I do love these cars.

My Z has developed a low rpm ignition miss. It started on the interstate in 6sp gear lug. I hadn?t replaced the plugs in a while so I replaced the plugs that evening (not expecting that to be the problem). I pulled the intake the next weekend and found the wire resistance off (9K) so I replaced all the wires. The wires had 30K on them and needed replaced anyway but didn?t fix the problem. I recently changed the coils to MSD 8224 coils.

Now comes the scary part. The miss is intermittent. Sometimes it does it misses cold, sometime it misses hot, and sometimes it doesn?t miss for a while. But it never dies or has starting problems, just a low rpm miss. You can hear the miss at idle, so I started pulling plug wires and found that the spark on cylinder one was weak/intermittent. All connectors on the ignition module are original but seem to be clean and holding tight. So I replaced the coil for cylinder 1/6. Also didn't fix the problem.

How does the ignition system fire cylinder 1 vs 6? It seems to only miss on cylinder one. Also when the rpm?s are above 3/3.5K it pulls through the miss and run well. When I pull the wire on cylinder 6 (same wasted spark coil) it has a strong spark. This really confuses me. It only misses on cylinder number one? Does the computer/ignition module give a separate command for cylinder 1 vs cylinder 6? I thought in the wasted spark ignitions that it just fired the coil on the same command for cylinder 1 and 6.

All other cylinder have good spark at idle. What could I be missing? If the timing pick up was bad, it wouldn?t always be cylinder one missing. Has anyone seen an Ignition module weak on only one cylinder? Can the computer cause this? Anyone have an ignition module for borrow/purchase? I know I am asking for a very rare part. Any thoughts? I am stuck at the moment. The way the problem started, I don?t think it is a control wiring shorting. I also don?t know how to test the ignition module or wires. Any help is appreciated.

Thanks
Brandon