Install a $3.00 ballast resistor & see if the problem solved. If not, you have an extra BR.

When mine went bad in my 71 Hemi Charger, I was driving it & it just quit. I pulled over on the shoulder & it started right back up, so I continued driving. About another 2 miles it died again, repeated the same scenario until I got to my buddies' house & there it sat for 2 weeks. It was getting fuel, & getting spark when we tested - WTH? So I started replacing inexpensive parts: coil, cap & rotor, elect. ign. module (I had extras), etc. It would always start & run, but then would cut-out. I finally decided to make the trek back to my place about 25 miles away & it died a few times on the way, but I made it. I was about to take it to an auto electric place & tried fiddling with it one last evening & started it & then observed underhood while it was running - saw a spark at the BR & it promptly died. I started it back up as usual, got out & wiggled one of the wires to it & it sparked again & died. I had an extra (old used) BR in my stash & installed it - problem solved. My story............