Jed, what kind of engine noise could you hear from your radio? I worked in a Delphi generator lab, and when we would get bad returns from newer cars (2002-2003) the engine noise would be a howling coming from the alternator. The howling means there was more amps pulling from the alternator than it could handle, which was for the most part a bad regulator.
so if your noise is howling = new alternator.
-Brad
