MY is really helpful when trying to find an issue as many times (like this) there are different possibilities.
Anyhow, the 997.2 w/ DFI has a known issue/recall on the HPFP. 997.1 can have issue w/ a short in the fuel pump / sending unit. 997.1's issue is hard to correctly diagnose particularly intermittently until it fails completely.
If you're under a warranty or even if not, next time issue occurs and vehicle won't start, have it towed immediately to a dealer/indy for diagnosis. They can pull the codes and trace back thru starting sequence to see what didn't occur and should have, etc.. Once it does start, the memory of the issue (as I understand) clears.
Good luck
