[V8] quiet ride over 80 mph...

[John Bysinger]

I have this odd problem... trying to figure it out.

My 90 v8 has an aftermarket stereo in it (no amp, just deck and 2 non-bose
speakers so far) and it has an interesting quirk.  When the speedo hits 80
mph, pretty much on the dot, the stereo shuts off, it doesn't lose power as
I can still eject the cd etc, but the deck thinks it's time for a nap.  When
the car comes to a stop, it will turn back on (or occasionally sometimes
while driving around 20 minutes later.)

The car did have an aftermarket deck in it when I bought it (a pretty sad
one at that, but there's telltale signs of an amplifyer being hooked up
before and the door panels have obvious signs of an el-cheapo stereo install
shops work (broken panel clips etc.)  So my guess is the previous owner had
a nicer setup, then put the bose speakers and a cheap deck back in before it
was repo'd (how I came to own it. :)

I've done many stereo installs so this isn't all new to me, and I checked
the ignition wire that the cheap deck was hooked up to to verify it does
indeed switch with the ignition, but this 80mph shutoff baffles me.  Is
there some behavior in the electrical system that triggers at 80mph?
Perhaps a stereo volume adjustment for higher speeds in the stock deck?

As much as I enjoy the sound of the v8 at 80+ it would be nice to have the
option of listening to music then as well...  Any help is appreciated!

-John
90v8q