How exactly does the EGR function?


Just wondering how the EGR and solenoid function. I noticed mine idles a bit smoother when the vaccum is removed from the valve, and thought maybe there was a problem there. TIA

The solenoid opens the valve at part throttle cruise. Some of the hot exhaust gas enters the intake system for better emissions and fuel mileage. It should not be opening at all at idle. If it does when you connect the hose, your solenoid may be leaking by.
The EGR valve should only open above idle when the engine is warmed up, if it opens at idle it will at least cause a rough idle, but usually cause the engine to stall. If you have vacuum to EGR at an idle then there is something wrong. Maybe a bad solenoid, a wiring problem or a computer problem