coil good but getting intermittent spark - delica

[barrettrussell]

As title reads. 2002 v6 6g72. plugs and wires 3k old. runs great when running right. Symptoms seem worse on warm days. by intermittent, I mean once it begins it often lasts the day, and wont happen again for another 5-100km. I swapped with another working coil and that one started behaving badly and the suspect coil(2/5) worked fine in others location (icm lead). Can the ignition control module be faulty intermittently on only one lead? i have never had an issue on other coils locations/ icm leads. Is there a way to test the icm lead when symptomatic? maybe with a test light for flicker? I tried with digi volt meter and the readings were no different than other leads that were working. I have no other specialized tools.

Thanks!
Barret