Hope this may help somebody with the same problem - it was driving me nuts!

92 Acura Integra LS - (original owner)

The sound to the front right speaker would cut in and out on a regular basis. After closer inspection, it seemed that if I wiggled the wiring harness to the back of the radio, the sound would cut in and out regularly. At first I thought it was a broken wire or loose connection from the wire harness plug to the radio.

After a bit of troubleshooting, this is what finally fixed it:

Removed the radio (stock cassette stereo).
Removed the I/O board from the back of the radio that has the connector for the power/speakers.

Got out my soldering iron and added a very small bit of solder to each connection on the back of the connector (it was more like heat it up and wiggle the connection a bit).
Low and behold my stereo sounds like new again.

(Thought for sure it was a loose wire)

Hope someone finds this useful,

Graham