Ford Taurus Electrical Issues

Hi- car is a 2003 Ford Tauras SES.
The electrical in the car dies intermittently. At slow speeds (idle), it will completely die, and requires to be put in park and restarted. At higher speeds it dies for half a second the dashboard lights flash on then off, and it continues (no need to restart). When this it happens it tends to make a 'popping' noise, probably because of the speakers. Also using anything electrical may cause it to happen, automatic windows, changing the radio station, the a/c level, etcetera.

Issue happened with both an old and new battery. The terminals are not corroded. The grounds appear intact. It happens completely intermittently, full gas, low gas, uphill, downhill, hot day, cold day, there is no set pattern.

Thanks so much for your thoughts.