Emission Systemm on 2004 Lincoln Navigator

my emission light started staying on & my navigator is not running smoothly. seems to be running rough and wants to stall. Any feedback would be helpful, I already replaced the DPFE sensor and the vehicle start driving smooth then start jerking again and it had cause my truck to go off couple of times. The mechanic check everything including spark plugs and coils. And the only alarm that comes on the computer is the EGR sensor

Asked by for the 2004 Lincoln Navigator
The EGR system will need to be checked and the problem properly diagnosed by an experienced technician if you wish to know what is wrong. Can you post the code that you have? Or check out our articles on EGR Fault Codes: http://repairpal.com/OBD-Code-P0402, http://repairpal.com/OBD-Code-P0401