Try to get the wing fuselage/fairings checked again and to check that the panel gaps are not too big, we had a triple seven that suffered from resonance and vibration around the wing root area and although the panels were properly secured, speed tape over all the joints cured the problem. finally cured by adjustment and sealing of the panel gaps.
Mind you we also had one doing the same and found an empty but rather battered mobil jet 2 oil can rattling around in the mix manifold
