All Models (Ported EGR Valve)
Disconnect vacuum hose from EGR valve. Run engine to normal operating temperature. Attach a vacuum pump to EGR valve. With engine idling, apply 8 in. Hg to EGR valve. If vacuum holds and idle becomes unstable or engine stalls, EGR valve is functioning properly. Reconnect vacuum hoses. Increase engine speed to 3000-3500 RPM. Ensure EGR valve opens.