70 Duster keeps shutting off

Ok so where is the fuseable link located do I have to take apart the bulkhead connectors to find it. The strange things is it will run fine for 20 miles one day before it shuts off and only run for 3 miles the next time. Or will start fine and idle for 3 or 4 min and then just shut off. There doesn't seem to be any rhyme or reason.