My 1994 Mustang has a 3.8 L motor and it starts great and idles perfect. But
every now and again the volt gauge will do a quick dip as if something with
a heavy drain like the fan on high was turned on. Then the needle will do a
little dance, dipping down for no apparent reason. This will also happen
when you are driving. The belt is ok, the battery is new and there is lots
of power in the battery. When the needle is dipping the engine isn't
changing at all, it's idling perfect all along. Any ideas what may be
causing this? I'm thinking a bad connection or maybe the alternator or
voltage regulator is ready to fail. Any help would be much appreciated.

Thanks!