If its p0401, remove egr then use a steel coathanger and push it through the port all the way through to the throttle plate. Clean the egr of carbon and vacuum test it. If it opens and. Closes as it should and holds vacuum, put it back on. If the light and code. Come back. Replace the sensor.
May, 16, 2012 AT 10:17 AM
Don't forget the DPFE sensor.
May, 17, 2012 AT 2:25 AM
A "clogged" EGR valve could not cause a poor idle, as it's supposed to be closed at idle. Pinging under acceleration, higher operating temperatures maybe. But it would have to be stuck open (or otherwise open when it's not supposed to be, which includes at idle) to cause a poor idle quality.
So, which actual code was this anyway? Because I can't think of any "low pressure" that would relate to the valve itself. It operate on vacuum not pressure. Maybe the pressure sensor, but not the valve.
If we had the actual code, maybe someone who knows what's what could clear this up, and save you a lot of money wasted on perfectly good parts being replaced?
May, 17, 2012 AT 10:13 AM
It can cause poor idling if the port is clogged all. The wau to the throttle plate. Because this will affect the idle. Air control valve. Remove this as well and check the pintle.
May, 17, 2012 AT 12:08 PM
With no code its a gess. Hi fail rate is the dpfe. None of which would make idle poor. Only if it was sticking open.
May, 17, 2012 AT 12:46 PM
It will if it's clogged with carbon and not allowing the pintle to seat.