So I just got off the phone with the place I got my alternator from, and I think the guy had some pretty good advice. First off, because I did the Big 3 SO freaking long ago (13 yrs) he suggested that I check all of those connections and make sure everything was solid (honestly, I think my mechanic already has... but anyway) and here's the big one.... That little lightweight plug that clips into the alternator.... Mine is 13 yo. He said those can wear out and get loose with time. Easy, and cheap to replace. Think I'm going to try this soon, as see if that helps....