A 6.0L fuel injector can easily get gummed over time, requiring a replacement.
The first step is to remove the fuel injector valve cover and then remove the CAC tube underneath. Additionally, a repairer needs to remove the wiring associated with the glow plug control module as well as the ICP sensor.
The second part is to then remove the standpipe from its position. The pipe could be long or short, depending on the truck engine configuration. The standpipe needs to be separated if it is a long version. Once the oil rail is removed then the long lower part of the standpipe can be put back into place. The oil rail bolts can then be removed and lifted carefully. Watch out for draining oil.
The third step is to position a 19mm socket so that it is secure on the injector connector. With firm pressure, the socket should be pressed in until the injector lock tabs release. The injector connect will then be free to be pulled up. Now the injector hold down clamp can be removed. The parts will come out of the injector bore as they are loosened.
At this point the inside of the injector bore should be examined to see if any of the copper seal or o-rings need replacement. If not, the new injector can be greased with clean engine oil and inserted after the hold down clamp is attached to it. The injector connector o-ring can then be greased and pushed into position until seating with a click. The position should be the same as the other injector connectors.
Next, before the oil rail is reinstalled, a bit of engine oil should be applied to the new injector top. At this point the rest of the parts removed can be reinstalled back in their original sequence. Engine ignition could take a while before the engine turns over after a change due to significant air in the system.