Does increasing the volume produce the problem more frequently?

All you can really do is check all the wire connections to each speaker and the head unit. To temporarily check if it's getting enough you could run a direct wire to your battery.

Sounds like a ground issue to me. You soldered all of your wires right :thumbsup

call crutchfield.com they helped me out.........

I guess I'd try hard wiring the 12V positives and ground, first. See if that clears it up.
High volume will expose inferior 12V power circuitry, like the 'Dog said. You'll see the lights on the radio dim, with the bass.
Then with a known good speaker, check the head unit, channel by channel - it could be defective.
Could be too, that the speakers are fried, and the higher wattage of the Sony is making it apparent for you. I always find out I that I also need new speakers whenever I upgrade a head unit or add an amp.:doh:

systronic said:

...problem now is, i put a new sony head unit in, but some of the speakers randomly cut in and out. i checked the wiring, and its all good.
should i bother trying to figure it out? or should i just hard wire a whole new system in? (probably what im gonna do)
anyone have similar probs?

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Did you remove the harness between the Sony and the Ford amp? That is going to cause problems if you did not! The harness that is connected to the radio goes the the amp then from the amp to a harness behind the glove box. If you plug the radio directly into the harness behind the glove box it should solve your probem. Also the premium system has the front negatives reversed... In other words hook the left front neg to the right front neg from your Sony. Not sure why ford did this with the premium system but I found this out by mistake.... I tested my speakers one at a time and the fronts where not working. Come to find out since the way the neg wire are done I was not getting a complete circuit because of this!

Yeah, hah hah, mine came with the fronts floating, or only one side was working, I don't remember. I straightened it out though.
My car has another set of connectors that look the same as the radio ones. Would those be for the amp? How do you tell premium sound on an '87 - '93? My '82 and '84 had badges on the dash, and switches. Would the amp be up under the center of the dash, like on a foureye? I don't remember seeing it.

LqDFx said:

Also the premium system has the front negatives reversed... In other words hook the left front neg to the right front neg from your Sony. Not sure why ford did this with the premium system but I found this out by mistake.... I tested my speakers one at a time and the fronts where not working.

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If you had the premium system, the amp would be right under the stereo behind the pocket. The ones behind the glove box are the same as the ones that the radio uses. Just use those.