Ok, my 2001 5.4 started bucking a couple days ago. I read the forums on this and put in a new IAC and a new EGR. Truck seems to be fine now except that now I keep getting the SES light coming on. (This started AFTER the new parts.) Code is a P1401: "Differential Pressure Feedback EGR Circuit High Input". I cleared the code and it keeps coming back on upon start up. Two questions: 1) Should I go ahead and replace this too? 2) Can you tell me where it is? (I just moved and somewhere in those boxes is my Chiltons!) Appreciate any help on this. Thanks!

 

I found the DPFE and the connection that I forgot reattach to it. "Stupid,Stupid,Stupid!" All's well now and the truck is running great! Thanks!