Wily father I suspect after power — tempt fate (4,4,4)
I believe the answer is:
play with fire
'tempt fate' is the definition.
(I've seen this in another clue)
'wily father i suspect after power' is the wordplay.
'suspect' indicates an anagram (a suspicious or unusual spelling).
'after' is a charade indicator (letters next to each other).
'power' becomes 'p'.
'wily'+'father'+'i'='wilyfatheri'
'wilyfatheri' anagrammed gives 'laywithfire'.
'laywithfire' after 'p' is 'PLAY WITH FIRE'.
(Other definitions for play with fire that I've seen before include "Expose oneself to unnecessary risk" , "Live dangerously" , "Be involved with something risky" , "Take dangerous risk" , "Risk disaster" .)