�1993 Nissan Sentra
1989-95 ENGINE PERFORMANCE Nissan EGR Function Testing
1) Disconnect vacuum hose to EGR valve. Plug end of disconnected hose. Connect a vacuum pump to EGR valve. With engine idling, apply vacuum to EGR valve. If vacuum holds and idle becomes unstable or engine stalls, EGR valve is functioning properly.
2) Ensure engine is at normal operating temperature. Connect a vacuum gauge to EGR hose. Increase engine speed to about 3000 RPM. If vacuum is shown on gauge, system is functioning properly.