I may be relatively new, but I'll throw my two cents in.
What I've learned from the site (mostly from reading old posts from Ray or Big Jim) is that the EGR valve usually isn't the culprit.
The problem lies with the DPFE (Differential Pressure Feedback) sensor. It's a small, rectangular box that's kind of underneath the upper intake... I'm sure somebody will pop up with a picture for you. Somebody always does.
Anyway, since these things operate in a harsh environment, they're prone to failure.
Symptoms of a bad DPFE would be CEL (check engine light) codes for "EGR valve excessive at idle" or "EGR flow insufficient." Other symptoms could include worsening gas mileage, rough or erratic idle, and so on.
Simple test for the EGR (courtesy of Ray): The EGR is the silver UFO looking thing connected with reddish pipe at the back of the upper intake. With the car running, take the green hose off of it (careful! it's brittle as hell), and apply a vacuum (suck on it!). If the car stumbles, the EGR is functioning properly.
Also, it might not be a bad idea to pull the throttle body off the car and give it a cleaning, as well as the EGR passages (the cutout section of the TB).
Ah, go nuts. Do a complete UIM/LIM teardown and clean. There is a superb FAQ in the Duratec Maintenence section.
Hope that helps.
Damn, just read that you had the Zetec... my infor generally applies to the Duratec. My bad.
Last edited by cobaltblue; 11/02/05 07:17 AM.
