1997 Chevy Cavalier All is dead except headlights, dome ligh

The car 97 Cavalier z24 2.4 Quad-4 is doing great, then I turn it off. Occasionally, not every time I go to start it. Nothing. Except the headlights, dome light and door chime. No instrument lights, fuel pump hum, radio, interior fan. Nothing.I figure a short somewhere, probably a ground.I leave the key on, check fuses and wiggle them and I check under the hood, thump the relays, wiggle wires, check battery connections. Most anything I can think of, but still nothing. So I kind of give up.I shut the hood and "PRESTO" everything comes alive and I'm on my way until it wants to play games with me again. It has done it twice only in the driveway. It has not done it going down the road yet but I'm expecting it to.I must find out what is causing this worrisome problem. It could be very dangerous if it happens at the wrong place.I have 3 of these cars and know them through and through, trust me.I think I am one of the best Quad-4 quy's around and intermittent electrical problems are the hardest thing in the car world to fix, but this one is giving me a brain tumor. Please, what do you think I should check next. (The computer brain is in the right front fender, I did not wiggle any wires on that yet) Thank you for any direction you can point.