Excellent diagnosis dude. I have exavtly the same problem. Usually when the car is running for a while and the engine is hot that when the old Icm trouble seem to be kicking in. I Bought my ICM for 50 dollars at autozone and replace it . No trouble since. TYPICALLY WHEN YOU ARE GOING TO CHANGE THE iCM , I would consider changing the Ignition coil as well since you are right there. Ignition coil is also around 50-60 dollars at autozone or advance auto. good luck.