All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If the finance company owns the car first and the car becomes in its possession before it sells it to you and the company does not set a condition that you will be fined in case of delay in payment, then it is permissible for you to deal with it, but if the company only pays the price on your behalf to the car company and then it gets the price from you with interest, then this is Riba (interest and/or usury) which is forbidden.
For more benefit on purchasing by installment and its conditions and the permissible and impermissible method of buying by installment, please refer to Fatwa 81662.
Allaah Knows best.