This site has been very helpful with my current EGR issue, but I've reached an impasse. My electronics experience is limited, so I'm hoping for some help diagnosing the problem. The jeep is a 1990 YJ, 2.5l.
My EGR is getting vacuum at idle, so, it idles rough or stalls out when the vacuum line is connected. The diaphragm appears to be working correctly: if I connect the vacuum source, the EGR valve opens and closes when I remove it.
The lower outlet at the EGR solenoid has vacuum at idle, so it does not appear that the vacuum canister is causing the issue.
There is no voltage reading across the pins on the solenoid connector at idle. There is battery voltage from the red wire to the negative battery terminal at idle, and battery voltage from the red wire to the positive terminal when the jeep is off. There is connectivity between the blue wire and the negative terminal when the jeep is off.
The CTS tested fine, per the FSM.
Any help would be greatly appreciated.