1985 pininfarina quits after 3 to 5 minutes

[18Fiatsandcounting]

I'm late to the party here, but the ideas already posted are good. It sure sounds fuel related (rather than electrical) to me, mainly because the problem mostly disappears if you remove the gas cap, and the fact that the car won't start immediately after it dies but will start a few minutes later. That doesn't sound like an electrical problem.

But, I have one question: When the engine dies, does it happen all at once and the gauges all go to zero at that point? Or does the engine sputter a bit and then die? The reason I ask is that if it dies all of a sudden, that sounds more electrical to me, whereas if it sputters for a few seconds and then dies, that sounds like a fuel starvation issue.

Other potential causes: A fuel pump that is cutting out, either because of a bad connection or because the inertial de-activation switch (I'm assuming this car has one) has gone goofy. This switch prevents the fuel pump from continuing to run if the car is in an accident, which could lead to fuel being pumped all over the accident scene (not good for safety, obviously).

-Bryan