Finished lower than second as idle (4,4)
I believe the answer is:
tick over
'idle' is the definition.
(I know that idle can be written as tick over)
'finished lower than second' is the wordplay.
I cannot really see how this works, but
'finished' could be 'over' (over can mean finished or ended) and 'over' is found in the answer.
'second' could be 'tick' (both can mean a very short amount of time) and 'tick' is found within the answer.
No letters remain.
This explanation may well be incorrect...
'as' acts as a link.
Can you help me to learn more?
(Other definitions for tick over that I've seen before include "(Of engine) idle" , "Run smoothly (or very slowly?)" , "Just keep going like idling engine" , "(Of engine) run slowly in neutral" .)