For a start I'd ohm the P module & see if it has basic continuity and give it a good visual (gap/anything loose or undone). I'm assuming it died while running which'd be on the ign1 (run) circuit & that the ballast was bypassed for the P system. What Stump said if it is still being fed (& likely it is) I'd suspect the P since you have changed out the coil. EDIT I reread & you still have the ballast (& it was replaced). I might be confusing the ballast elimination recommendation with standard MSD install procedure