It sounds like the engine has a miss. The most common reason with the Expedition is a coil pack. What I recommend is to have the computer scanned at a nationally recognized parts store. They will most likely do it for free, and if it is one of the coil packs, it will identify which one it is.
Let me know and I'll direct you as to what needs done.
Sunday, January 4th, 2009 AT 1:52 PM