What year? What engine?
The ICM works with the PCM to time and trigger spark. The PCM needs to receive signals from the crank and cam position sensors. The PCM will then signal the ICM to fire the coils. Replacing the ICM may eliminate that as a possible problem, but the rest of the circuit still needs to function from the PCM to the coils.
Since the system uses a wasted spark scheme it is also important to have clean, dry spark plugs to be certain that spark energy is not simply shunted to ground by a shorted/wet plug and that the plug wires are in good condition.