Installed an xo vision xd103 using butt connectors and scosches car stereo install kit in my 93 mercury grand marquis (ford stereo) and everything is fine except one speaker buzzes. i tried re connecting it with a new butt but its still there. it only buzzes when the sound is on. and on occasion the stereo itself seems to come and go. like it\'s high and then low, then high then low, but its not constant or consistent. what am I doing wrong?

Audio Players & Recorders - XO Vision - XD103 FM and MP3 Stereo Receiver with USB Port and SD Card