Originally posted by spocket:
The EGR ports were not clogged on my old UIM.
So it seems that the P0401 hasn't been fixed at this time. Is that correct?
Originally posted by spocket:
I just come back from taking the EGR valve off the car and it seems fine. It is actuating when I put vacuum on the top.
My EGR valve opened when I applied vacuum also, but when I took a further look it was totally clogged. I took the EGR valve off the engine, opened the valve with vacuum, and then shone a flashlight in one end. I couldn't see any light coming out the other end (even in complete darkness). This showed me that the EGR valve was completely clogged.
Originally posted by spocket:
Could the DPFE cause the "bucking" at low rpm?
The DPFE is just a measuring device. It measures the amount of exhaust that is flowing through the EGR system (specifically the venturi tube).
The EVR (EGR vacuum regulator) is the device that actually opens and closes the EGR valve. It's possible that the EVR is erratically opening and closing the EGR valve. This could cause the engine to stumble. But this seems highly unlikely.
