I need your help
 

My 1990 911 keeps going dead as I pull up to a stop sign, red light, etc. I have a guy that will work on it without losing a couple of rooms of my house and a small child. Although he is an excellent mechanic, he is not that familiar with Porsche engines. He needs to know what to change out. Here are the following guesses:

1. DME relay
2. Possible vacuum leak
3. Ignition coil and wires
4. Torque the manifold bolts down. Check the torque setting. I know on the carrera's it at 18 ft/Lbs
5. I was told there are 2-3 switches/relays that could be the problem, but I am not sure what they are called (any idea).

I know it is hard to diagnosis someone's problem without seeing the car, but I sure appreciate you trying. Thanks.

Head temperature sensor. Located on cylinder 3 (left side of the motor, rear cylinder)

Bad DME relay: Car will not start
Vacuum leak: Car will run like garbage
Ignition: Same thing
Manifold bolts: Not likely

AFJ

Thank you so much. So, forget the vac and ignition and concentrate on the head temperature sensor?