1997 Chevy Monte Carlo Problems Starting the Car

Hello, we have a '97 Chev Monte Carlo which has intermittent starting problems. Every so often when attempting to start the car, the car won't start - it's just completely dead. If you wait a few minutes and try again, it starts with no problem. There is a chip in the ignition key for this particular vehicle. We've had the car in to two different shops and no one can figure out the problem. I don't believe the car had a factory installed theft system, but one has since been installed. HOWEVER, this starting problem was present befoe that system was installed, so I'm not sure if the problem ties into that or not. Any ideas? It's a great car with no other problems so we'd like to get this fixed so we can drive the car without worrying about the car starting!