EGR Valve
- Bring engine to normal operating temperature and operate at idle. Disconnect and plug vacuum hose at EGR valve. Engine should run smoothly.
- Connect vacuum pump to EGR valve, and apply 5-10 in. Hg. Engine should run rough. Release vacuum to EGR valve. Engine should return to normal idle speed. If engine does not run rough or does not return to normal idle, clean or replace EGR control valve.