hey there - new to these forums so I hope im in the right place. I need some advice for my 99f150. 4.6 (w) with 160000 miles on it. I keep getting the CEL. took it to auto parts store and got EGR insufficent flow code 0401. I have replaced the EGR valve, the DPFE sensor, the solenoid, I have taken out the throttle body and cleaned it out, cleaned everything I can think of and I have resetted the computer at every step of the way and still CEL came on after 35 miles of driving. I am at my wits end - could use any advice.

 

use a hand held vaccume pum and suck a vaccume on the egr valve,if the engine stalls the valve and port are ok. if it dosnt then the port isnt totally free.

 

Also, if you are using an aftermarket DPFE sensor, it could be your problem right there.