costs or cost

[Peter Petrov]

In a book I see the sentence below:

My neighbour bought a car that/which cost $40,000.

I think the sentence must be with costs, because that/which = it (car).

Is it true?

[Rover_KE]

In a book I saw the sentence below:

Always cite the title and author of any published text that you quote.

My neighbour bought a car that/which cost $40,000.

I think the sentence must be with costs, because that/which = it (car).

Is it true Am I right?

The verb 'cost' is in the past tense because he bought it in the past (even if was only two minutes ago).

[Peter Petrov]

The book is Essential Grammar In Use 4th edition by Raymond Murphy.

The page is 213. It is the last sentence.

Thanks for the answer. I missed that.