Ultimately drove Vauxhall right into ditch - weird! (8)
I believe the answer is:
eldritch
'weird' is the definition.
(synonyms)
'ultimately drove vauxhall right into ditch' is the wordplay.
'ultimately' indicates one should take the final letters.
'right' becomes 'r' (common abbreviation).
'into' indicates putting letters inside.
The last letters of 'drove vauxhall' are 'el'.
'r' going within 'ditch' is 'dritch'.
'el'+'dritch'='ELDRITCH'
(Other definitions for eldritch that I've seen before include "Weird Scots" , "Weird, sinister, ghostly" , "Weird Scottish" , "Spooky" .)