a bad coil will take out an ICM. i replace them in pairs and have done so the last decade. i also replace the coil when putting in a new/rebuilt distributor. played musical coils/ICMs/distributors on a buddies squarebody dump truck a few years back with 2 Accell brand amazon distributors. i finally said enough and put it my big cap gm performance HEI, and has had zero issues since.