Alternator/generator/regulator problems of the 1998 Nissan Altima

After arriving home safely from a long highway drive (7 hrs), our car sat for about 5 hours. When I started the car, I smelled smoke and heard a unusual rubbing noise under the hood. After popping the hood, I saw smoke pouring out of the alternator. I turned off the engine, went inside to get a fire extinguisher. The fire was still burning, but seemed to be inside the alternator. I extinguished it and hopefully saved serious engine damage. The car was towed to the dealer, and is awaiting service now.

The car was idle at a red light when it shut down completely (engine, radio, lights, etc). It would not start again. I got a jump and it started. The next day it started fine. I let it idle for about 15 minutes and it was okay. I drove it for a few minutes and it died again. I had it towed to a repair shop. None of the diagnostic tests showed anything wrong (battery, alternator, etc. Were okay). They drove it and it did not die again. I took it to a Nissan dealer and they cannot find any problems either.

Several times the vehicle wouldn't start, I had to have it jump started. Usually happened after it had been driven for a short time, stopped and then tried to restart. One time it wouldn't start even with a jump. Battery was replaced and it continued to happen. Dealership could not duplicate the problem. All readings for battery and alternator came back normal.

The electrical system failed and sometimes the car won't start. I replaced the alternator and battery, but it still happens.