rattling noise under hood on passager side near alternator and after driving 180 miles when coming to a halt the car shuts off but the headlights dont

how many miles on the odometer? any visible things that look out of the ordinary(coolant seepage, excessive oil, smoke ) around that area? speed and engine rpm at time of rattle? how does the rubber belt look? there are several possiblities.

The rattling noise is probably the electric clutch on the AC compressor. Next time you hear the noise, turn the AC on to see if the noise stops. The engine stalling is another matter. Probable cause would be a vacuum leak.

change the spark plugs wires to youl save gas 2