Well I started to troubleshoot my EGR system. The first thing I did was remove the vacuum to the EGR valve and while the vehicle was idling I applied vacuum to the EGR valve and the car stalled. For the time being I am assuming that the EGR valve works and the ports are relatively clear.
I then wanted to check the EVR but it was at the back of the engine and it was cold so I moved on.
I started to look at the DPFE. I am no too sure how this sensor works but I think if it senses a difference in pressure from it's two inputs then this would indicate that the EGR valve is opened. If the sensor detects equal pressure then the valve is close (so I believe).
At cold it should read less than 1 volt and between 4 and 6 volts at hot. (this is from my Haynes)
For some reason mine reads about 4.67 volts at cold and remains that way. I was not able to take it for a drive to fully warm up but I did let it warm up in the driveway and it never changed.
I then thought that perhaps it is seeing a pressure difference at cold. It does not make sense since the engine idles nicely.
As an experiment I disconnected the two exhaust inputs and measured the signal voltage. Again it read 4.67 volts. I assumed that this is equal pressure on both inputs (atmospheric) and should be the equivalent to no flow through the EGR.
I am almost positve this sensor is malfunctioning but I wanted someone else to review and comment on my logic.
Thanks