So your problem is going to be one of the primary ignition components. These components are
Pick Up coil
The short cable between the ICM and the ignition coil
Power to the Ignition coil
The magnet in the rotor of the distributor.
Since you replaced the ICM and that didn't fix it we can eliminate that one, at least for now.
The easy tests -
With the engine running wiggle the wires coming from the harness to the ignition coil. If it cuts out you have the the problem found.
Next try the cable between the ICM and ignition coil. Again if it cuts out you have it figured. btw, I sell these new on my website if you are interested - http://www.reddevilriver.com/2.html
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Next if both of those make no difference take a screwdriver and knock the metal base of the distributor while running. If the engine coughs then I would expect the pick up coil to be the cause of the problem. The pick up coil tends to go bad over time. The glue falls apart, the insulation fails and the whole thing looks like it is failing.
If you find nothing with the easy tests then you should use an ohm meter and test the pick up coil with the meter.
Note - you don't need to remove the distributor to test the pick up coil. You do however need to remove the distributor to replace the pick up coil.
In case you need it - replacing the pick up coil
Removing the distributor
Replacing the pick up coil
Replacing the distributor
Timing the engine after replacing the distributor into the block
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[This message has been edited by phonedawgz (edited 05-06-2014).]