Radio Volume Problem

[supertug]

All,My wife has a 85 300ZX 2+2 and we are having problems with the volume on the radio. She had the factory unit replaced a number of years ago and it works fine. In the last few years, a bump in the road will cause the volume to drop drastically. Thinking it was a problem with the radio, I replaced the unit last week, however the same drop in volume still happens. Does anyone have an idea as to what may be causing this? Is there a particular way the speaker wires are run in this car? I thank everyone for their input with my problem...SuperTug

[evildky]

I'd try an seperate ground wire from the chassis of the stereo to a good chassis ground

I seem to recall some of them having a remote "amplifier" and if it's acting up you could replace it or just get a more modern unit (with cd) , and run wires directly to the speakers to bypass any other possible problems alng the way