Drive down over a city in Florida (5)
I believe the answer is:
tampa
'city in florida' is the definition.
(I've seen this before)
'drive down over a' is the wordplay.
'drive down' becomes 'tamp' (I've seen this in another clue).
'over' is a charade indicator (letters next to each other) (in a down clue, some letters go over others).
'tamp'+'a'='TAMPA'
(Other definitions for tampa that I've seen before include "stateside destination" , "US resort" , "American resort" , "US town" , "Port of western Florida" .)