Chase, I am talking about the 2.6 motor. I do not know the EGR system on the 2.8V6's.
EGR does not work most at idle on this motor(2.6), it works more as the throttle opens. If you open the EGR under idle with the motor, it will kill the engine. The vacuum solinoid is on a thermistor and as the engine warms up, the solinoid opens to allow vacuum to the transducer. When the transducer gets exhaust pressure, it will open up and allow the vacuum to reach the EGR vavle to open it and allow the exhaust gases in to the intake stream. The exhaust pressure will still open the transducer and allow the path of vacuum to be available to the EGR under cold conditions, but if the thermistor isn't warmed up and open, it will not allow the vacuum over to the transducer.

Also, there are electronically controlled EGR vavles, as the second generation Troopers are controlled this way.