in case anyone cares, lol..swapped an acm and that did nothing. I have a good suspicion this is EGR related. lately my soot level will go to 100%, it will actually do a passive at this point, but never before 100%. It will drop the soot level down to about the 2nd "e" in Soot Level Gauge in about 80 miles. Then I get the check engine light with the SPN 2659 code telling me I have low EGR flow. I clear the code and do it all over again. I have replaced EVERYTHING on the EGR system except wiring and whatever is controlling it. EGR Valve,Cooler,update Venturi Pipe,EGR pressure sensor.