Car stereo works, sometimes
 

In my 1987 MR2 the factory radio doesn't really like to work all that much. Sometimes it comes on when I start the car and sometimes it doesn't. On the off chance it does work when your listening to music it will never randomly turn off when you drive, go over bumps, etc. I'm not sure if its just a loose wire or something. Weather and temperature don't seem to be a factor.

Electrical problems like this one can be quite challenging to diagnose, because it's a failing connection _somewhere_ that is obviously intermittent. You're going to need some knowledge of electrical systems, a wiring diagram of the car and either a multimeter or a test lamp. If you're not comfortable reading wiring diagrams, there isn't a whole lot someone can post on a forum to help you out...unless they're intimately familiar with your particular year/model.

Do you have a wiring diagram for the car?

-D

Yeah I have a wiring diagram here.
http://opc.mr2oc.com/online_parts_ca...electrical.pdf
The reason that I posted this here is that I was wondering if it was a common problem or something that could be fixed with replacing a fuse or equivalent small part. Would just getting a new radio fix the problem. Seems like a whole mess of shit to mess with.

Pull the stereo out and check the connections to the car wiring (specifically the red and yellow wires), then report back.

You didn't mention if it loses memory or not after it turns back on.

I have a couple of factory late 80's toyota decks that you can try out if you want, couple of them from 84-86 mk1a mr2's, nice to see another mr2 around!

It's probably just pissed off at you. Stop playing Nickelback CDs.

If bumps and things don't have any effect I'd lean more towards the circuits of the old deck acting up over a wiring issue, the caps in that deck have been through 28 years of summers and winters so they might be drying out.

I believe that you're right underscore.

Unless you're going for collectors plates, you should consider a bluetooth deck to replace the factory one.
I used to own that exact car. The stereo was the first thing I changed. Your speakers may be retiring soon too. As with all car parts, they do have a limited life span. Investing into new equipment is just part of keeping an older car on the road