Couldn't decide if San Diego was lousy (8)
I believe the answer is:
agonised
'couldn't decide' is the definition.
(as in agonising over a difficult decision)
'san diego was lousy' is the wordplay.
'was lousy' indicates an anagram (a lousy spelling of the letters).
'san'+'diego'='sandiego'
'sandiego' with letters rearranged gives 'AGONISED'.
'if' acts as a link.
(Other definitions for agonised that I've seen before include "experienced pain" , "Was in great doubt" , "worried a lot" , "Very pained" , "suffered a lot" .)