EGR Vacuum Regulator Solenoid
WARNING: This page is about a different car, the 1995 Mazda B4000, 1995 Mazda B3000, and 1995 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect vacuum hoses and electrical connector from solenoid. Ensure vacuum does not pass through valve ports. Apply battery voltage (positive to Red wire terminal) to solenoid. Vacuum should pass through valve. Replace solenoid if necessary.