Drop around for fuel (3)
I believe the answer is:
gas
'fuel' is the definition.
(gas is a fuel)
'drop around' is the wordplay.
'drop' becomes 'sag' (sagging is a kind of dropping).
'around' says the letters should be written in reverse.
'sag' written backwards gives 'GAS'.
'for' is the link.
(Other definitions for gas that I've seen before include "Talk profusely" , "Idle chat" , "State of matter not solid or liquid" , "Chat (colloq.)" , "Hydrogen possibly" .)