EGR Vacuum Supply
Locate EGR vacuum supply port on throttle body or intake manifold. Disconnect vacuum supply hose and connect hand-held vacuum gauge to port. Start engine and increase engine speed to 2000 RPM. Check vacuum gauge. Gauge reading should be greater than 20 in. Hg vacuum. If gauge reading is not at least 20 in. Hg vacuum, check vacuum supply port for restriction (carbon, dirt, etc.).