Car stereo system issues.
 

I think that electronics is better than motors for this, only because it deals with just the car speakers/amp. If I'm wrong, can a mod move this for me? Thanks.

When my father sold me his old car a year ago, the front passenger-side speaker had not been working at all for a while. Accepting that as a given, I never really gave it too much thought. Last month, I was messing around with the equalizer, and I kicked the bass up all the way. That front speaker suddenly started working, albeit quietly and with much less bass response than the others. I put the equalizer back to normal, and it kept working for maybe a week before dying again. The head unit is the factory default (Pontiac, 1999), and the speakers were replaced and the amp added in maybe 2003-4. Is this a speaker issue, can it be the connection from the amp, or could it be the amp itself? Thank you very much for your knowledge and advice.

It could be the amp or speaker.
Easiest thing for YOU to check is the krimp on connectors at the speaker. You could also check the other end of the speaker cable. It may mate with the amp through a plug-socket arrangement with the radio housing bracket.
If it's the amp you will have to send it to a repairman.

If you know how to use a multimeter, check the resistance between the two speaker wires at the amp side of the speaker cable. Connected to the amp or not.
Should be less than 10 ohms - more than 3.

If the amp is easily accessible, switch the "bad" speaker to another socket and see if it starts working. That'll tell you if it's the amp itself or not. If the speaker continues to malfunction, it's the connection, or the speaker itself.