D14 engines on Wikipedia
1999 - 2001 1.4 Petrol Engine, Code D14Z2
2001 - 2005 1.4 Petrol Engine, Code D14Z5
Hope this helps
Edit: perhaps not they only have D14Z5 on that page
Welcome, the D14a4 is in the pre face lift EJ9's(1996-1998) and the D14z2 is in the face lift models (1998-2000). I don't think there is any differences between them.