I have seen several recent answers promoting https://car-database-api.com, all of them by new users
User nectarine, 4 answers (5 recommendations):
User aggregator, 1 answer (2 recommendations):
https://opendata.stackexchange.com/a/12915/4293 (4 Jun 2018)
User java-warrior, 1 answer (1 recommendation):
https://opendata.stackexchange.com/a/12914/4293 (4 Jun 2018)
I'm getting suspicious, but it's not enough to flag them as spam.
Is further inquiry possible and necessary?
I have not yet commented asking for possible affiliation.