Exhaust Gas Recirculation
- Ensure all vacuum hoses are correctly routed and securely attached. Replace any crimped or broken hoses. Ensure there is less than one in. Hg vacuum to EGR valve at idle with engine at normal operating temperature. Install tachometer. Disconnect Idle Air Control (IAC) wiring harness connector. Remove and plug vacuum hose at EGR valve. Place transmission in Neutral.
- Start and operate engine at idle. Note idle speed. Using a hand-held vacuum pump, slowly apply 5-10 in. Hg vacuum to EGR valve. When vacuum is fully applied, engine should do one or more of the following:
- Engine should stall.
- Idle speed should drop more than 100 RPM.
- Idle speed should return to normal when vacuum is released.
- Service or replace EGR valve if engine does not stall or idle speed does not respond as specified. Reconnect IAC harness connector. Unplug and reconnect vacuum hose at EGR valve. For additional EGR system testing and specifications, go to TEST HE: EGR SYSTEM
under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.