The TDC sensor is quite easy - just need to get underneath the front of the car. The connector breaks down first because it's old and exposed to the elements. If it becomes disconnected (ie by bouncing about while driving) the ECU doesn't know when to fire, and things stop running. Wiggle the connector with the engine running, and if it cuts out, there's your problem. It's restarting again while your driving because you're effectively bump starting it.