After extracting the PKG file, you'll need to create a PS3 install package. This package will contain the game data and installation scripts.
On a standard PS3, PKG files are digital packages used for games, updates, or DLC purchased from the PlayStation Store. PKG files are encrypted containers.
Do not just Google "download blur ps3 pkg" and click the first link. Most are dead or malicious. Instead, look for these trusted sources in the scene:
The game loaded. Not to a menu, but directly into a car.
You might be spending hours trying to get this search result to pay off. Is the game still good?
The modding community often preserves delisted games.