The victim was assaulted after the two culprits test drove the vehicle which he was trying to sell on June 17.
The alleged buyer picked up a friend during the journey – but acted suspiciously when the owner asked him for the money.
The men punched and kicked him to the ground after he removed the keys from the ignition – trying to steal the keys back.
The robbers then fled with the log book for the car after the incident at around 6pm on Hurst Road in the city.
Police have released CCTV images of two men they want to speak with in connection with the attempted robbery.
Anyone with information is asked to call the police on 101 quoting crime reference number 20WV/139859P/20.
Alternatively, contact Crimestoppers anonymously on 0800 555111 or at crimestoppers-uk.org