EGR Valve
- Install tachometer. Disconnect IAC solenoid connector. Disconnect EGR valve vacuum supply hose. Start engine and operate at idle with transmission in Neutral. Observe idle speed. Engine should run smoothly.
- Connect vacuum pump to EGR valve and slowly apply 5-10 in. Hg. Engine should run rough and idle should drop more than 100 RPM. Release vacuum to EGR valve. Engine should return to normal idle speed. If engine does not run as specified, replace EGR valve.
Courtesy of MAZDA MOTORS CORP.