Because of the electronic shift control, I would suspect alternator going out and/or battery going bad. A bad battery can cause the alternator to not always give enough juice to the other components as it is trying to compensate. A bad alternator might not be keeping up with charging and at times the battery gets also low during those rpms. Take it to a AutoZone or Advance parts store and they will test your charging system and battery for no cost to at least eliminate that as a possibility.