Well back in Aug I took my 2000 exp to the dealership to get it checked for a chatter in the engine. The tech told me the computer showed a slight prob with the coils for 1 and 4 cylinders but they werent too bad to change out yet and the tapping was spark knock from one or both of the coils not firing as it was supposed to. I was told it was ok to drive until one gave out and the check engine light came on, then the could figure out with one was the cause. Didnt sound like a spark knock to me, but I'm not a certified mechanic so ok. Today, as I was driving on interstate, I heard a pop, and the sickening sound of a motor going sour. I dont have proof yet, but I believe it broke a valve and quickly went downhill. So now I have to put in a motor. Ford wants $4300 for a 5.4l installed, Jasper wants $5200 for just the engine. I can get a 4.6l cheaper, which is my main goal, since the thing is only worth about $6000 on a good day. I know the blocks should interchage and the 4.6l should bolt up to the tranny with no prob. Can I go this route? Will the EFI and computer for a 5.4 work on a 4.6? What other issues will I have in doing this?? Oh yeah, FYI the check engine light never came on even after it blew up! Thanks for the help.

 

Depending on the extent of the damage, you may be able to get away with just replacing the heads. You would need to tear it down to see what needs to be done, though.