Parking attendant taking so long with Tesla (5)
I believe the answer is:
valet
'parking attendant' is the definition.
(I've seen this in another clue)
'so long with tesla' is the wordplay.
'so long' becomes 'vale' (I've seen this in other clues).
'with' says to put letters next to each other.
'tesla' becomes 'T' (scientific unit).
'vale'+'t'='VALET'
'taking' is the link.
(Other definitions for valet that I've seen before include "Gentleman's assistant" , "Gentleman's gentleman" , "Male servant" , "'No man is a hero to his . . . . .'" , "Man's servant" .)