89 camaro 2.8 liter fuel pressure regulator problem

I changed the head gasket on my camaro, and now that I've put it back together the fuel rail is leaking fuel from what the shop manual calls the fuel pressure connection (it's the fitting on top that I believe is used to relieve pressure before working on the system). There is the possibility that I may have screwed up the vacuum lines going to the fuel pressure regulator, since the vacuum diagrams omit certain components. Also, the pictures in the shop manual show the connection as having a cap, which is missing. However, there was no leak before. Anybody have any ideas as to why it is leaking, or more importantly, how to stop it? Any info and/or help will be greatly appreciated.