[leegreen]

you said it had 50+PSI fuel pressure, but does it hold that pressure for 5 minutes after you turn the key off? The injector spider is a known source of leaks on 4.3

I'd also find out what your long term fuel trims are, they will indicate what the computer thinks is happening. If you scanner does not do it, get a Bluetooth OBD2 dongle off amazon and a copy of torque pro for your phone.

plugged cat sounds like too much fuel, if the computer is trying to trim lean but not getting there a leaking spider could be the culprit