Left work in American sucker's tin lizzie (6)
I believe the answer is:
jalopy
'tin lizzie' is the definition.
(both can refer to an old car)
'left work in american sucker's' is the wordplay.
'left' becomes 'l' (common abbreviation).
'work' becomes 'op' (abbreviation for opus).
'in' is an insertion indicator.
'american sucker' becomes 'jay' (US term for a stupid person).
'l'+'op'='lop'
'lop' inserted within 'jay' is 'JALOPY'.
(Other definitions for jalopy that I've seen before include "Old vehicle" , "Rundown old car" , "Dilapidated old car" , "wreck" , "Old and unreliable car" .)