Problem with 1990 Grand Prix radio

The problem may be a short in one of the speaker circuits. Remove the radio from the dash, butdon't unplug it. When the problem occurs, use a digital meter to measure the DC voltage on each speaker wire. Place your meter on a 12 volt DC scale and measure between a good ground and each speaker wire output. The speaker out wires are in two differnet spots in the plug. The rear speaker wires are brown, yellow, light blue, and dark blue. The front speaker wires are light green, dark green, tan and grey. These wires should have about 6 volts on them with the radio on. If they don't then either that speaker wire/wires needs to be replaced or the speaker is bad. If everything checks OK, then the problem is likely in the radio. You may also be able to lightly tap the radio with a screwdriver to see if the problem is a bad connection in the radio. A lot of radio shops can also test the radio if you are unsuresparky

If there is a short in one speaker can it affect the other ones?  All of my pass side speakers make the noise, not just one of them.  Caould it be an amplifier problem?

The problem could be a short in one or more of the wires to the right side speakers. If one wires is shorted more may be too. They do run along the same paths at times in the car. Try what I mentioned and I am sure you will locate the cause of the problem. If any one of the speaker wires shorts to ground or 12 volts, all the audio will cut out from the radio.sparky