Ported EGR Valve
Warm engine to operating temperature. Increase engine speed to 1900 RPM on non-turbo engines or 2600 RPM on turbo engines. EGR valve should open. Disconnect vacuum hose (upper hose on EGR valve with 2 hoses) from EGR valve. Apply vacuum. Engine should idle rough or idle speed should drop.
Warm engine to operating temperature. Disconnect Red-stripped hose from modulator valve. Apply vacuum to hose. If engine RPM drops, EGR valve is okay. If engine RPM does not drop, check hoses, connections, and vacuum tank.