My old Bug Eye used to have what I can only describe as a hand brake cable twanging sound when backing off but closer to the door behind me, after much searching, tightening & someone hanging their head out the open back door it turned out to be the Bosch fuel pump.

__________________
Beaten up old 98 Gen 2 Liberty, 13.0, stock V3 STI running gear.
07 Transit motor home
69 VF & 70 VG Valiants needing full restoration
Yamaha Zooma 50cc rocket hopefully going with the Transit.