Ford 5.4L Spark Plug Removal
First step is removing the ignition coils. This takes a 7mm socket. Once the coils are removed, you may find it easier to remove the PCM and bracket from the passenger side of the engine compartment to get to cylinders #3 and #4. Removal is simple. Unplug the three connectors, remove the 4 bolts that hold the PCM to the bracket, and then remove the 3 bolts that hold the bracket on.
Now I will go into the several ways mentioned to remove the spark plugs from first hand experience. I have found the success rate will vary dramatically depending on your chosen method. It appears that if the spark plugs are destined to break, they will break no matter how you attempt to remove them. No one method will work all the time.
The most reliable source, Ford, has released a Technical Service Bulletin on how to remove the spark plugs. The TSB 08-7-6 can be read entirely HERE. Loosening the plug and spraying it with something similar to Wynns EGR cleaner seems to work sometimes. I personally do not have much luck with it. I use a 3/8 impact gun to remove the spark plugs with a hot engine. This method works about 70% of the time for me. You will probably need a 9 inch extension, u joint (swivel) adapter, and a 3 inch if not using the spark plug tool mentioned earlier. In short bursts like shooting a gun, slowly tap the trigger until the plug is removed or broken. This is my preferred method. Get it over with quickly. If it breaks, it breaks; I'll handle it.
I have had success in my own vehicle by running fuel injection cleaners through the engine prior to changing the spark plugs. I performed a professional fuel injection cleaning service, then used products similar to SeaFoam weeks in advance. I was able to remove all 8 from my vehicle without any breaking. I have been able to test using high performance intake decarbonization cleaners used by our dealership with varying results. Check out my article Fuel Service in a Bottle for some tips.
You can remove them by hand tools if you feel safer. Once the socket is on the plug, slowly apply torque to the plug. Try to keep the socket centered on the plug while you break it loose as lateral forces almost always break the porcelain. If the plug comes out easily, you probably broke it. If it fights you the whole way out while making horrible screeching noises, it probably came out intact. This is my least preferred method because it takes the longest wastes the most energy.
If its broken: Pull out the top part of the plug for inspection. You must determine what is left in the cylinder head. If lucky, the piece you pull out will have a complete electrode attached (metal rod sticking out the end) with only the tip stuck in the head. If the electrode is broken off flush, it needs to be removed from the plug well with pliers before using the lisle tool. If you can not remove the electrode, proceed at your own risk as the first step of the tool will likely break a large chunk of porcelain to be laying on the top of the piston. Any extra porcelain needs to be broken and removed prior to installing the tool. Make sure to blow out the cylinder with air or shop vac it to remove all debris before removing the stuck plug. Follow the instructions included with the tool.
Once the old plug is removed, make sure you coat the extended portion and the threaded portion of the new plug with a little anti seize. Do not get anti seize on the tip of the electrode as it can cause misfires. Make sure you tighten the plug down sufficiently as they will come loose if you do not. Autozone replacement plugs have been notorious for coming loose. If it does work it way loose, you will likely need to replace the coil if it damaged by combustion heat.
Congratulations. You now can change the remaining 7. If you start to do this for a living, I would go ahead remove all spark plugs and install the new plugs in the holes that came out fine before addressing on the broken ones.