can an oregon car dealer sell a vehicle when they don't possess the title or registration i their possession?

A dealer is not required to have the title and they are not required to put the vehicle in their name. They are required to send certian documents to the DMV while they obtain those documents, called a Transitional Ownership Document or TOD. So long as they have the release from all previous owners, they do not need to ever submit the Oregon title (althea could submit a 515 instead, with appropriate releases).

Technically if they have a bill of sale. They can prove ownership. That being said, they should get the title before they sell it. However it is not always available as they are paying off a previous loan before they can get it from the lender. So there are things in place to allow them to prefect the new lien with the new sale if they do not have the document. It’s called a TOD or transitional ownership document they file with the DMV.

A used dealer isn't supposed to sell a car without having the title in possession. In fact, in most states, it's unlawful to do so. Until the dealer has the title, issued in the dealership's name, the company doesn't officially own the vehicle