Beat time unevenly, her combo following (5)
I believe the answer is:
throb
'beat' is the definition.
(throbbing is a kind of beating)
'time unevenly her combo following' is the wordplay.
I cannot really understand how this works, but
'time' could be 'hr' (I've seen this in other clues) and 'hr' is found in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for throb that I've seen before include "Beat like heart" , "Sound of engines" , "Have strong or irregular heartbeat" , "Martin -; Kingsley -" , "Pulsate strongly" .)