Bringing back to life three 1979 Mustangs !

[SuperDuty455]

I followed your advice an rebuilt the carb, it was well needed. A lot of crud at the bottom of the tank, and some oxydation on the brass pieces.

All cleaned, everything put in the same place (idle mixture screws, choke, float,...), all the holes and cavities cleaned.

But despite that, no luck...same issue.

My last resort was replacing the new coil and putting back the old one, but the I checked the connections at the duraspark module...and the big rectangular one was not completely in. Not by much, but a "click" away...

Now it works perfectly again
I feel kinda dumb though, but a lot of stuff are new now and it forced me to check a lot of things.