Tell you again and again to get fuel (6)
I believe the answer is:
repeat
'tell' is the definition.
(I know that repeat is a more specific form of the action tell)
'again to get fuel' is the wordplay.
'again' becomes 're' (prefix meaning 'again').
'to get' means one lot of letters go next to another.
'fuel' becomes 'peat' (peat is a kind of fuel).
're'+'peat'='REPEAT'
'you again and' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for repeat that I've seen before include "Ditto" , "Echo words" , "Reiterate" , "old TV show" , "Iterate" .)