It´s very possible that the rubber in the jets and carbs is old, hard, and brittle. This in effect acts like a constant choke because of the leakage and it then shuts of till it cools and drains at wich time its able to be started again. I could also need fresh fuses or if the ECU is cracked or damaged and has received a lot of water. If it has lots of miles (greater than 50,000miles) there could also be a problem with valves.