[cadillac_tech]

The passages are ok if the eng bogged. Get a helper for a quick test. Have your helper brake torque the engine while your fingers are under the valve(about 1/3 throttle). The valve should lift up. If not, pull the vacuum hose and see if it has vacuum during brake torque. If not, check for manifold vacuum to the solenoid. These are the first and quickest checks to make. If the valve opens on the first check and the engine bogs at idle like you said, your NOx problem is elswhere.