take a close look at the bulkhead connector on the firewall.
Disconnect it and look at all of the terminals. You may find a corroded or melted wire. I had a 69 dart that would quit running while driving down the road.
![](/ubbthreads/images/graemlins/runaway.gif)
Totally dead. I would turn on something that I could see from outside the car (like headlights)and then raise the hood and wiggle the bulkhead connecter until the power came back on.
![](/ubbthreads/images/graemlins/thumbs.gif)
Slam the hood jump in the car start it up and drive until the next time it happened.
![](/ubbthreads/images/graemlins/laugh2.gif)
Corrosion was my problem but some of these get so bad that they melt because of high resistance.
The previous post was good advice. Get a test light and start at the battery . Its most likely the bulkhead connector or the amp gauge. Read this article:
http://www.madelectrical.com/electricaltech/amp-gauges.shtml