I have a CEL so I pulled the codes and got a P1635 and P1400. The truck has been running like crap for about a month. My book says a P1400 is "Diff Pres Feedback EGR Circuit Low Input".

What I need to know is, does this sound like the DPFE sensor? I am covered by Ford's extension program on the DPFE since it is a 2001, but if that's not the problem, I don't want to have to pay them for services un-rendered. Thanks!!!

 

Well guys I called up a buddy in parts at a local dealership and the upgraded DPFE sensor is normally $90, but since Ford is replacing like 30 per day at this particular dealership, they are only $14.95 cost right now. I picked one up and slapped it in, cleared the codes, and it's doing great for now. I will keep you posted. No sense taking it to the dealership for the warranty extension...it would cost than $15 in time and gas to have them tear into your truck.