Sounds like your EGR valve might be stuck open.

Ok, so I changed out the FPDM yesterday, the old one was corroded and a mess. No holes through it but it looked fairly bad. (I would like to post a picture, however I cant figure out how to make it work in the forum).

The expedition fired up right away after I changed it but it stumbled a bit later that evening. This morning it hesitated a bit, but I cannot be sure that wasnt just my imagination. At this point, ALLORO, how would I troubleshoot/narrow down that the EGR valve is sticking?

An update to previous post--trying to keep this thread alive-- the Expedition is having issues again. Same issue, slower starting and a bit of a stumble right upon the motor turning over. Last night it took an extended crank to turn over and the check engine light came on. As I will most certainly NOT be going back to the dealership I went to last time, I will be ordering a code reader/scanner from Amazon today. I'll post any results.

And, annnnnnd, the code was................?

Once I receive the code reader and use it I will post it, but since I am ordering it today, I don't know yet.

So..... code reader arrived - then an unexpected move delayed the repair and posting. So I read and cleared the codes. The system was showing a P0301: Cylinder 1 misfire detected. I cleared the code and restarted several times, all with no MIL illumination. Drove the vehicle for about a week then it kicked back on again. Since that time frame the MIL kicked off and on a few times.

About this time my Texas state inspection was due and without thinking I took it in with the MIL lamp lit up. So after $39 I was ever so graciously told that I failed because the light didnt shut off once the vehicle was started. The printout shows fault codes P0301: cylinder 1 misfire (again) and P0172: System too rich (bank 1).

So at this point, I certainly will not be going back to the dealership I went to previously, but I plan on spending the next few nights under the hood retracing vacuume lines and hoping that's it.

Any other suggestions -- I am hoping that it's not the fuel pump.

Why would you waste your time with vacuum lines? You have a trouble code telling you that cylinder #1 is misfiring.

At this point I am checking anything and everything I can because I am at a loss of what to do next. I had previously suffered from a MAF sensor failure due to a cheap air filter dissintegration; in a different incident I suffered from a cylinder #1 misfire and MIL illumination. After replacing all of the plugs, the coil over the number 1 cylinder (to the tune of around $800) it did it again.

Now I have the codes showing cylinder #1 misfire (again) as well as a right bank running rich. Now, admittedly I am far from a professional -- and I am sure someone will correct me if I am wrong -- but I have found some information on the internet that led me to believe that a cracked or damaged line may result in increased fuel being delivered -- resulting in the rich code.

As for the misfire -- I am stuck. I don't know what else to check next. Any and all help is always appreciated.

You may have a leaky fuel injector. Try swaping injector #1 with injector #2 and see if the misfire follows.

thank you pdqford, I will give that a try my next day off. I have also found some info regarding the fuel pressure regulator possibly causing the issue.... sounds like a busy day off.

Just an FYI, if your 2005 has an FPDM it will not have a typical "fuel pressure regulator" with a vacuum reference.

It will have a combination fuel rail pressure/fuel temperature sensor. (This sensor has a vacuum hose connected to it, but it is not vacuum referenced. The vacuum hose is there, should the diaphram rupture, to carry any fuel leakage to the intake.)

The PCM uses data from this sensor and sends commands to the FPDM. The FPDM controls the speed of the fuel pump based on the commands received from the PCM.

Yes - I apologize - I misspoke on the part name. The fuel pressure sensor was what I was thinking. I have already changed out the FPDM (which was corroded on the back side - not as bad as I have seen on the internet but bad enough to warrant replacing). So at this point the dealership "claims" to have changed out the spark plugs, the coil over #1 cylinder - I have changed out the FPDM.

The next day off I am going to check the #1 plug (just to see the condition), the fuel injector, the fuel pressure sensor, all vacume lines and lastly the fuel filter (just above the tank) --If all that yields no effects, I am going to test the fuel pump and ensure I am getting adequate pressure out of it.

If none of that works, I may resort to setting it on fire. }>

i had the fpdm problem also -wondering if there is or should be a recall

That would require that Ford admit there is a quality and/or design flaw. So in other words...nope. :)

Having the same issues as reported by OP, does anyone know if 04 Navigator has the FPDM?