I have been working on the same issue. everything from the EGR,Fuel pressure valve, Idle Control, Throttle boby and more have been looked at and serviced. We thought it might be the EVAC (because when the line from the top of the EVAC to the intake manifold was pinched the idle settled to 800RPM and there was no vacuum at the EVAC when there should be except during start-up)so a used one was installed. Still in process but what we think the problem is is the little vacuum pot that is on a line that exits the bottom of the EVAC. After an autopsy on the old EVAC, there are no valves inside.Either way, it is most likely a vacuum leak of some sort in some location ('tis the crux). Try pinching vacuum lines in a systematic order once engine is idleing slow and you will be on your way...the line below the EVAC is not easy to see/get to. I'll attach some pics after Christmas.
Dec 24, 2011 at 6:04 PM
