1996 is different from 1999 and newer as the PCV valve is in the REAR valve cover on the older ones......they moved it to the front valve cover in 1999.
However, the advice is still good......just harder to see the hose.
The vaccum line from the PCV valve goes into the TOP of the upper intake manifold, near the throttle body.
That flexible elbow (90 degree) on the top of the upper intake manifold can crack, mine cracked on the INSIDE of the elbow, but also check the whole hose.
Connecting the IMRC in the closed position....make sure to fasten BOTH of them closed.
You may still get a CEL for them being in the closed position (unless you don't accellerate hard enough for the PCM to try to open them), but it should improve how the vehicle runs, low end power, and fuel economy.
That EGR tube, like mentioned, may need the help of someone with skills.....as it is likely corrosion/heat glued in place.
The EGR flow sensor (DPFE) senses the difference in pressure between the 2 hoses.
There is a restriction inside that metal tube, between the 2 hose connections.
More flow = greater drop in pressure between the bottom hose and the top hose.
Contrary to what some think, EGR flow is CRITICAL to optimum operation as it not only decreases polution, but it reduces temperature in parts of the motor.
Short term not critical, but long term is not good at all.
It is still possible that the DPFE sensor is defective, but....as you mention, that repair job on the hose connection to the metal pipe is a suspect.
I wonder if some high temp header or exhaust wrap might help?........too hot for duct tape (bad joke).