Modifies starters of any dodgy automobiles prone to stalling (6)
I believe the answer is:
adapts
'modifies' is the definition.
(I've seen this in another clue)
'starters of any dodgy automobiles prone to stalling' is the wordplay.
'starters of' suggests taking the first letters.
The first letters of 'any dodgy automobiles prone to stalling' is 'ADAPTS'.
(Other definitions for adapts that I've seen before include "Adjusts to new conditions" , "Converts to a different use" , "fashions" , "Alters to suit another purpose" , "Modifies for a new use" .)