The speakers in my Loyale occasionally go in-and-out, or give a buzzing noise when sound goes through them;  this all mostly happens on the passenger side. I have noticed that when I press certain buttons in the car, it affects the speakers, sometimes causing them to start working normally. This is what has had an effect: Pressing the 4wd button (not even all the way), adjusting the electric mirrors, raising or lowering the passenger-side window, and opening/shutting the passenger door (it may be the seat belt that does it). I have replaced the speaker in that door, and the problem has not changed. It was working fine for several weeks up until recently. Anybody have any thoughts? Thanks!

That's odd...  any oem speakers are likely shot just due to age by now.  Wires in the link to the doors can break and be intermittent. 

The driver-side speaker actually works very well! I haven't bothered to replace it just in case something goes wrong. The wires in the doors was the best thing I could come up with too, especially since the window and seat belt are a bit wonky in that door too. 

I forgot to add that sometimes taking a tape in and out of the tape deck will affect the speakers. I'm thinking it would be good to check the wiring from the radio to the door. 

I liked the oem radios, as they were very good at am.  But they started failing about 10 years ago.  I put in Nakmichi units, and new speakers,  using the existing wires.   Now I also have Bluetooth and hands-free cell phone.

The speakers in my '86 went kablooey (technical term) in just a few years after being a new car. Some electrical malfunction, maybe moisture got into where it shouldn't have. Still have the original set-up, just know to not turn the radio on, it makes some awful staticky noise that makes you lose the will to live.