My 1978 Thunderbird starta right up then it quits in traffic and won't start for a while. After sitting runs no prob.
It could be the coil getting hot. Or something in distributed if it does it again check to see if the car has fire at the plugs
You are describing a classic ignition module for those years, most likely it has a blue grommet where the wiring goes into the unit, most part stores will have this in stock, it might be a good idea to replace the distributor pickup inside the distributor at this time, especially if it has never been changed. That too should be at your local parts store.
I had the same problem on one of my 65's and I replaced the coil (which was fire hot after running) and the ignition module. Now it runs fine.
Looking for a Used Thunderbird in your area?
CarGurus has 1,046 nationwide Thunderbird listings starting at $7,500.
Search Ford Thunderbird Questions
Ford Thunderbird Experts