I have a 2001 expedition with the 5.4 and 2wd if that makes any difference. 170k miles when accelerating in the 1000-1800rpm range my Expedition shakes and the engine stumbles until around 2000 rpm than its fine after 2000 rpm. If rpms drop below 2000 rpm than the truck starts doing it all over again. I replaced the fuel filter yesterday and one coil about two months ago and the boot and spring for another coil today. The truck started doing this about a week ago. I have noticed that there is coolant on the outside of the spark plug boots on the number 1 and number 4 cylinders, I have also replaced the head gaskets, intake manifold gaskets, throttle body gasket, new coolant, oil, etc. The previous owner told me that the fuel pump was recently changed but i do not know if that's true. I need this Expedition as its my only vehicle other than my wife's and she needs her all the time for school and work. Please any help would be greatly appreciated. What are the chances that it could just be the coils need to be changed? Maybe fuel pump? oh and when fuel filter was changed the gas that came out was black.

 

Replace the spark plugs and all the boots/springs.