Just had the alternator and belt changed out on my 03 Camry and now after driving for about an hour straight in bumper to bumper traffic. The car will suddenly drop idle and the lights will dim and battery light will flash. Also the radio which isn’t stock suddenly working and it’s about a week old but before it stopped working it used to shoot out a lot of static.

 

Get a volt meter and check voltage at battery engine RPM at around 2000, should be 14-15v.

Guessing you have a bad connection at battery, alternator wiring, ground wiring, bad battery.

Any items causing large electrical drains such as a mega watt amplifier?

 

Voltage was around 14.3V and I still have the factory amp. Going to check ground soon. Another question is the idle control valve. Where is that located because my idling tends to go up and down when stopped at a res light or traffic.

 

The idle is control by the throttle which is electric. Try cleaning the throttle body.