Check Engine light is on..need help

[USMCWHITENER]

My 1996 has an issue that I can not pin-point...The code is P0401 - "EGR Flow Insufficient". I have replaced EGR valve, both O2 sensors, EGR Presure Feedback Sensor, and PCV Valve...still have the code coming on....and now i'm late on buying the tag for it this year..because it wouldn't pass emissions....If someone can help me try and pin-point my problem..it would be greatly appreciated. Thanks in advance

 

[E4Ranger]

My moms 2001 had the same code and i replaced all the components you listed above, the code went off and has stayed off for a month now. i did all the work with battery disconnected, so at start up the ecu would be clear and read the new parameters. did ya do this? or you can go by a parts store and they can clear it for you. hope this helps out. ohh-raa!