Find fault with motoring organisation about parking (4)
I believe the answer is:
carp
'find fault' is the definition.
(I've seen this before)
'with motoring organisation about parking' is the wordplay.
'with' is a charade indicator (letters next to each other).
'motoring organisation' becomes 'rac'.
'about' is a reversal indicator.
'parking' becomes 'p'.
'rac' written backwards gives 'car'.
'car' put next to 'p' is 'CARP'.
(Other definitions for carp that I've seen before include "Fish - complaint" , "Pond fish" , "Fish < and beef" , "Fish often kept in ponds" , "Raise trivial objections" .)