Up for guesses, item #3
Cut off end of a heater core pipe?
Very worn ( out ) idler arm bushing. The one that attaches to the center ( drag ) link ? I’m probably wrong though, as gauging by the coins used for a size reference the ‘mystery’ part looks a bit small.
Automatic transmission linkage bushing?
getting warm…
A homemade brake pedal bushing?
Home made clutch pedal ( support ) bushing ?