what is causing my 2004 Lincoln Navigator to shut down unexpectedly while driving with no warning.

I've been having the same problem with my Navigator!

Same problem with 2007 except it only did it once and hasn't started back up since. bout to pull my hair out , what little I have left, going through fuses, relays, checking for power to fuel pump etc..all I do know is that after it died on the freeway and wouldn't start back up is, the power seat that hasn't worked for months began working and im not getting any fuel to the rails.. EVERYTHING else on the vehicle works fine. ie...all electronics, nav system, radio, dvd etc...turns over fine just will not start. Can the anti theft system somehow cut off power to fuel pump? It cranks with starting fluid, so I know its firing.

Sounds like the fuel filter or fuel pump going bad. Carry a rubber hammer and hit the gas tank when it dies, it may work temporarily.

Did you ever figure it out? My 2003 navigation dies sometimes and then I just put in park and it starts again but it’s scary when you are are the highway and it does it.

I had this problem in 03 navigator. Changed out fuel pump, ect. Finally had to replace fuse panel, because in this particular model they built the fuel relay into the fuse panel. Hope this helps someone else. We had to spend a lot of money to figure this out.

M 03 did same thing. Changed out fuse box an it solved the problem