The DPFE does not directly control anything on the engine. Only the PCM does that. Normally, there is NO EGR flow at idle or at WOT. It is entirely up to the programming within the PCM as to whether or not EGR flow is commanded based on the operating parameters built in to it.
As to your repeated question, please refer to my last comment above regarding multiple problems.
You will have to clear the reason for the 327 before you can intelligently proceed further.
I suspect your DPFE is defective, but you also have an additional problem, perhaps caused by the extended period of time that the condition causing the 327 has been there. Possibilites include a stuck open EGR valve, faulty IAC, or some other intake vacuum leak.
Steve
