Car:
1998 Nissan Altima
2.4 liters
4 cylinder
168K miles

While I am driving at seemingly random times, all the power will totally go off in my car for one or two seconds. If it stays off long enough, the engine shuts down. There seems to be nothing that ties these instances together. No strange sounds or anything else.

All of the power goes out, the power comes back on, and a few lights on my dash may display for a second or two.

It may happen twice in one day, and not happen again for weeks.

In the past year, I have gotten a new battery, wires, new connectors for the battery, gotten my alternator tested and it seems to be ok.

What could the problem be?