Firing into gin, I staggered (8)
I believe the answer is:
ignition
'firing' is the definition.
('ignition' can be a synonym of 'firing')
'into gin i staggered' is the wordplay.
'staggered' indicates an anagram.
'into'+'gin'+'i'='intogini'
'intogini' is an anagram of 'IGNITION'.
(Other definitions for ignition that I've seen before include "Starting of combustion" , "Beginning of combustion" , "Kindling process" , "Mechanism to start car engine by sparking fuel" , "Internal-combustion engine's firing system" .)