Mine has the premium sound system, EQ and all, just the reception sounds fuzzy, it's not the speakers, replaced them, it almost picks up as well with antenna down, but you can tell a difference with it up, sometimes the signal is good and it sounds real good, but most of the time it sounds like week signal, is there anything that can be done to help this?
I have the same problem on an 88 without the premium sound option.. I checked my speakers too and they are fine. My antenna doesn't go down, but I have tried unscrewing it and putting another one on to no avail.
THe contacts on the "mixer" (L/R, F/B treble/bass) can get corroded and randomly start buzzing really bad. Right now only my left rear speaker works. If I play with the s I can get buzzing out all the other speakers but no audible sound.
I took out the radio and EQ, cleaned contacts, re installed and it sounds better to me, might want to try that, I didn't think it could hurt and I think mine helped.