Present provided inside fast car (4)
I believe the answer is:
gift
'present' is the definition.
('gift' can be a synonym of 'present')
'provided inside fast car' is the wordplay.
'provided' becomes 'if'.
'inside' is an insertion indicator.
'fast car' becomes 'gt' (I've seen this in other clues).
'if' placed inside 'gt' is 'GIFT'.
(Other definitions for gift that I've seen before include "Natural talent" , "flair" , "Knack" , "bent" , "Special aptitude - present" .)