Quote Originally Posted by zak View Post
Coupe of things to think about - the TAB/TAD solenoids on the fender apron (drivers side, at least on a 5.0 CFI) can dry rot out, not set a code, and fail to control air injection properly resulting in some symptoms you list. As another poster mentioned, PIP can be bad, not hard to R&R. Finally, the bearings in the distributer could be bad, pull it and see if there is play.
gonna devise a way to maybe bypass the TAB/TAD, probably just plug the vacuum lines and go from there. also gonna drop the Y-pipe if i can borrow a friend's low-pro floor jack. maybe replace it for the one we have laying around.