If you fix the context, then the asnwers lose thier scope. So I intentinaly left out the context so that I could garner all possible meanings/interpretations (i,.e. scope). I believe this would only be possible in the absence of context as then there could be probably only one meaning.Then it is the context that implies it, not your sentence.
Thank you for your asnwer. Then, it means that it implies that the speaker MAY have more then three or less then three.Your context-free sentence implies nothing. It is pointless to try to discuss the meaning of an isolated sentence with no context. All that it means is that, in the past, you were the owner of three cars. It says absolutely nothing about the present, distant past, or future.