Have a 99 E-250 with the 4.2 V-6 with that code. I have replaced the EGR valve, DPFE sensor and the EGRvacuum regulator and checked for any vacuum hose leak. Still get the code after replacing those components. Truck feels like it's down on power and mileage has taken a big dip. Any ideas as to where I should look next will be greatly appreciated. Thanks for your time!