[Halon]

Are you on E85? 1600's are tricky injectors. From my experience, they don't work all that hot on normal pump gas. They work better when you start using E85, but are still a little tricky.

Are you running pump or e85? If you are running e85, have you looked to see if you've accumulated some of the mysterious black goo on your injector tips? If you are running e85, I'd personally remove the injectors and let the tips soak in a small container of regular gasoline for 15 minutes to "clean" them. Reinstall and see if you notice a difference.

But in the end, keep in mind that 1600's are just tricky in general.