Spectacularly terrible car stereo...

It's been like this for about two years now, ever since I got the car, and has gotten marginally worse recently. But, the storm had nothing to do with it...it was my evacuation vehicle.

Unless the previous owner of your car was... well, crazy... it's highly unlikely you've got a separate amplifier. 1990s Chevy Caprices are not known for being pimped-out. What's more likely is that the previous owner took out the old heatunit and put in the new one, or that Chevrolet offered a "luxury" Bose headunit option. Or, that someone took a Bose sticker and put it on your stock radio. Any one of those is more likely than having a separate amp. If you had a separate amp, you'd probably know by now, because you would have seen it in the trunk or behind the seats. This sounds like you've got two problems: one, that the wire connections to the speakers are flakey, and two, that your headunit is dying. These things happen. Here's your basic car stereo diagram: Inside the cabin are your seats, a dash, and some carpet. Inside the dash is your headunit. There are wires running from the headunit behind the dash, through the doors into the door speakers. If you have rear speakers as well, that means there's another pair of wires going from your headunit inside the dash, underneath the carpeting, probably through some hole in the trunk, and up behind the rear deck (where your rear speakers are located). Most headunits have built-in amplifiers. The only ones that don't are usually phenomenally expensive (Nakamichi, McIntosh, etc.). If you had an external amp, the wires would go from the headunit to the amp, and then from the amp to the speakers. Since space is at a premium in car cabins, the amp is usually mounted in the trunk. Yes, that means there are wires running all over the place under your carpet. Annoying, huh? The procedure to remove your old headunit differs from car to car, but basically it involves removing the part of the dash that sits in front of the headunit, then removing the headunit itself (usually nothing more than a couple of phillips-head screws). To remove or fix the door speakers, you'll have to take off the interior door panel cover. There will be a few steps that, again, differ from car to car. If you've got an armrest, that unscrews from the door. If you've got manual roll-up windows, there's a clip that holds it on. Once you've got the "stuff" off the door, the door panel itself can be popped off (it's normally held on with a bunch of plastic clips). Rear speakers are much easier. Just pop off the grill and unscrew 'em, or alternatively unscrew them by gaining access from inside the trunk. YMMV. If you don't have any experience with holding a screwdriver, or are just afraid of breaking something (it happens to the best of us), I'm 100% certain you could take it to just about anywhere (Best Buy, Sears, etc.) and they'll install a new stereo and speakers (and speaker wires) for you. Alternatively, you can check out http://www.crutchfield.com and find a new headunit that fits your car, and they'll even send you the correct wiring harness (the connector that goes from the back of the headunit to the other parts of the car so it "knows" to turn on when you put the keys in the ignition, and the like).

What C_D said. http://www.crutchfield.com/S-gFrNZiP1ZwA/ (click on "What Fits My Car" under "More Ways to Shop" on the right.) You might be able to use this to determine how your system is structured (e.g., does it have a separate amp or not?) I plugged in 1993 Caprice and it appears Bose sound was an option so there's a good chance this is the original system.

This is a problem that has a $120 solution (I'm actually about to do this with my girlfriend's 1994 Ford): drive your car to the local electronics retailer / installer (e.g. Circuit City, Tweeter), pick out a CD radio, and have them install it. Don't waste your time trying to understand it, just take to the pros* and let them do the install. They do this all day long and there's nothing special about your setup. You can get CD/cassette/radio combo units, but I ... as an engineer I wonder about the reliability of something like that that has so much jammed into one package. Don't replace the speakers, don't get satellite radio, don't get an external amp, just replace the head unit and move on with your life. In glorious four-speaker sound. * pros = surly teens / 20-somethings, probably

I think it's very unlikely you have a seperate amp. I think it's one of two things, roughly equally possible. The first is the connector behind the stereo. It's come loose. The second is inside the stereo and beyond your ability, or reason, to repair (I'd guess it's the connections on the circuit board right before the amp). I'm inclined to think that the second possibility is more likely because a) the consistency of the speakers working and not working; and more importantly b) the high-pitched noise. If it's reasonably easy for you to reach behind the stereo from below the dash, or by removing only a few things, or by easily pulling the stereo from the dash, it's worth the efffort to do so and just mess with the connector a bit and see if that makes the speakers work (and not work). Otherwise, get a new stereo.

Civil_ Disobedient and Opposite George have the right idea. I was browsing through the Crutchfield website and bought an inexpensive Dual brand CD receiver to replace my aging JVC brand CD receiver. Shipping was super quick, supplied instructions and tools all worked great. It took one hour to install since I had to splice a few wires in the car (the last professional installer didn't have the GM wiring harness on hand, so he spliced the wires). My new CD receiver has MP3 playback and an external jack for my iPod that I installed in the glove compartment.

Thanks for all your answers! I just went outside and looked in my trunk and I have something that I'm 99% sure is an amp. That is, it's mounted below where the speakers are, it's about the size of hardcover book, and wires run in/out of it. Also, my big clue: it says BOSE on it. I tried taking a picture of it, but needless to say it's sorta tough to take a cameraphone picture of something in your trunk. I don't know if that changes anything. Also, I'm not trying to be obstinate, but if I can at all help it, I really don't want to just walk into a car stereo place and be like "I dunno." In my hierarchy of people who rip off the ignorant, car stereo dudes are up there with mechanics and computer repair guys. (Blame a terrible run-in with Best Buy, where a girlfriend's surprise birthday present ended up costing LESS than the "free install.) Again, if anyone's reading this thread...thanks!

Well, I'll be a monkey's uncle. It does change things. Could be the amp. The things I wrote could apply to the amp or the stereo. I think you should jiggle some of the connectors on the amp to check that possibility.

Chevrolet offered a "luxury" Bose headunit option ... which probably came with an amp. Most of your premium radio upgrades do. Heck, my '89 Ford Probe had a "premium" sound system with a cassette deck, four speakers -- and an amp under the front passenger seat.