My '74 has been doing that for a long time. Make sure the electronic control unit is free of rust on the mounting bracket and tight on the fender. Also, I have heard that if there is something on the passenger seat the switch may keep it from starting if the seat belt is not connected. I think this may be unique to '74's, but I am unsure if it is true or not. I just bounced up and down on the seat a couple of times, and my car seems to be starting all the time now. The good part is it costs nothing to try. Hope this helps, I can't stand electrical glitches.
OOps, I'm a minute late.
