Since official Sony servers for PSP are offline, use these trusted fan sources:
If you are playing on an emulator, the official PPSSPP forums have user-shared save states and standard save files. cars+2+psp+save+data+free
Make sure you didn't accidentally nest the folders. The directory structure must look like SAVEDATA/ULUS105820000/PARAM.SFO . If there is an extra folder layer in between, the system will not recognize it. If you want to customize your experience further, Share public link Since official Sony servers for PSP are offline,
If you are running the game virtually, you simply need to place the extracted folder into the emulator's virtual memory card directory. Documents -> PPSSPP -> PSP -> SAVEDATA cars+2+psp+save+data+free