Longest stretch between two films?
- 23 years between Psycho (1960), and Psycho II (1983).
- 20 years between Rambo III (1988), and Rambo (2008).
- 19 years between Indiana Jones and the Last Crusade (1989), and Indiana Jones and the Kingdom of the Crystal Skull (2008).
- 16 years between The Godfather Part II (1974), and The Godfather Part III (1990).
- 16 years between Star Wars: Episode VI - Return of the Jedi (1983), and Star Wars: Episode I - The Phantom Menace (1999)
- 16 years between Rocky V (1990), and Rocky Balboa (2006).
Any others come to mind?