EGR Valve

Remove EGR vacuum hose and attach vacuum. Apply 10-12 in. Hg to EGR valve while checking for smooth operation of diaphragm. Verify that diaphragm will maintain position without loosing vacuum. Replace EGR valve if performance is not satisfactory. Start engine and idle. Apply vacuum to EGR diaphragm. Engine should idle rough and/or stall. If diaphragm moves and engine RPM does not change, remove EGR valve and check for plugged passages.