Thrust mixture with little reliability when carbon is delayed (7)
I believe the answer is:
pierced
'little reliability when carbon is delayed' is the definition.
I can't judge whether this defines the answer.
'thrust mixture' is the wordplay.
'thrust' becomes 'pierce' ('pierce' can be a synonym of 'thrust').
'mixture' becomes 'd' (I can't justify this - if you can you should believe this answer much more).
'pierce'+'d'='PIERCED'
'with' acts as a link.
Can you help me to learn more?
(Other definitions for pierced that I've seen before include "stabbed" , "Holed" , "Impaled" , "Run through" , "Punctured" .)