Does anyone know why when on my 03 Expedition when I give it gas sometimes especially between 40 and 60 mph it feels like the fuel flow is cut back. It is like I am trying to run and someone is holding my shirt and then lets me go. There are no lights on the dash showing. The fuel filter has recently been replaced. It will sometimes run like a 5.4 should with power and other times very sluggish. any ideas? thanks