EGR system not operating correctly...

[Mustvid]

Here are the details... please read everything before you offer any advice.

1. The car is a '92 5.0 with a consistent rough idle and rich fuel mixture problem. It bogs at tip in/low RPM.

2. The following parts have been replaced and have been tested as good.

EGR valve
EGR position sensor
ECT sensor
IAC valve

3. Running codes produces:
034 (EGR Valve position sensor voltage above closed unit)

Here's the rundown on the EGR system. The EGR valve and position sensor are new and test out. The green vacuum line coming from the EGR vacuum regulator solenoid actually pushes air out into the EGR valve at idle and produces very little vacuum at higher RPM. I can see no visible movement of the bladder in the EGR as I rev the motor with the vacuum line attached. With the EGR valve disconnected, the car seems to smooth out and power is regained.

Does it sound like the EGR vacuum regulator solenoid is bad? What are the symptoms? How would the car run with the EGR staying in the closed/open position?