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[dadomin8r]

OOOOOHHHHHH my time to put two cents on Ford's expeditions and the 5.4L. I had a 98 with a 5.4. about 70k miles and the thing sounded like it had an exhaust leak. My lazy butt didn't fix it right away and at 80k the spark plug in the #3 (it's been a while i think it was the #3) blew out of the head along with the threads. I took it to the local mechanic (mistake 1 that I will never make again, take it to FORD, those guys don't invest in the tools it takes to fix the new motors) and he put a solid helicoil in it (Cheap way to go that ford won't do). The damn thing still missed every once in a while.......long story short, it took a lot of money at 3 dealerships and a lot of cursing at the local mech, to find out that the missing was a tear in the coil pack boot. Even when they put a new boot on it would tear, because you have to flex it around the fuel rail. The rubber (whatever it is) is SO cheap, it tears putting the thing in. The tear causes it to arc to the head. It is a very common problem in the expeditions especially but in a lot of 5.4L motors as well.

Ford went with an aluminum head and used a plug with half the threads. Common sense tells you that this isn't the wisest choice, but the real problem is on Ford's assembly line.

Take it to ford and have them check which cylinder it is (hard when the miss is intermittent) and check the coil pack boot for a tear or test the coil pack itself. You can't really check which cylinder it is w/o their $$$$$$$$ machine. [img]/ubbthreads/images/graemlins/shocked.gif[/img]