Ok guys, I'll keep it short.

4 months ago engine in my truck failed (failed lifters in 2 cylinders). Had engine replaced, the engine came from a wrecked 2005 expedition with 12K miles. Mechanic checked Vin codes to make sure the engines were the same. First 3 months truck drove beautiful. Now when cruising all seems fine but when I mash (full throttle) on the gas on highway to get to speeds or to pass someone the truck will hiccup like it is backfiring, loose power then start going again. Some times the loss of power can last until I get of the gas. Also now I am noticing when I mash the throttle I get huge amounts of white smoke out of the tail pipe.

Any ideas?

Truck specs before engine failure:
2004 Screw, 5.4L 3 valve auto 100k miles
Now:
2004 Screw, 104K miles on truck., 2005 5.4L 3 valve 14K mile engine.

 

Without seeing it myself the white smoke leads me to believe blown headgasket. Check your plugs to see if there is coolant on the tips.

 

White smoke would typically be a head gasket. I would get a compression test done. Are you losing coolant? Did he use the injectors from the 05? They had some bad injectors that could cause the power issues. Any cel?

 

Did you reuse the 2004 engine's injectors, or do you have the '05 injectors installed?

 

I'll check the coolant this weekend. I am not sure if the mechanic used my injectors or the ones from the new engine. When the truck was finished I was not around to ask.

 

As far as the engine "backfiring" or "hiccuping" goes, you may want to check the fuel level next time you stomp it. One of the first things i noticed about my truck was when it was low on fuel, there is no way in hell im pulling out in front of someone. It acts as if the fuel pump is about to die, but no sir..... its fine, just really, really low on fuel.

 

What about a bad fuel filter.....

 

You put in an engine that could possibly have bad fuel injectors. All 2005 5.4's have this issue.