The first thing to do when replacing your Jeep's fuel injectors is to relieve the fuel system pressure. Disconnect the battery always, because you are dealing with electrical and fuel, and a spark could cause a bad fire. At the end of the fuel injector rail (the bar that all the injectors are attached to), there is a round knob. Hold a rag under this knob and slowly loosen it until no more gas goes into the rag. Always wear safety glasses during this process, because fuel can accidentally squirt just about anywhere, and it is important to protect the eyes and face. Once all the pressure is alleviated, it is safe to unbolt all the attaching points of the fuel rail and slightly lift up. It is attached to the manifold at four points using 13 millimeter hex bolts.
Detach the fuel lines from the rail and the injectors themselves. Also recommended is to detach the vacuum hoses that go to the throttle body so the fuel system is completely isolated. The throttle body can be found under the air cleaner, and takes the place of a carburetor. If you disconnect the lines to the coil as well, the entire fuel rail assembly can be removed from the engine, making it easier to work on individual components. Also unplug the electrical connections from each fuel injector, so you are left with only the injectors and fuel rail. It is recommended to change out all the O-rings on each fuel injector at this point as well, which will restore good pressure to the fuel system and prevent future problems.
With the fuel rail disconnected, you will find that each fuel injector is held in place by a clip, which can be removed by hand. It is very important not to lose these clips, because they will be necessary for reinstallation. With the clip removed, the injector will pull right out. Do not damage the fuel rail, because they are impossible to repair, and a new unit will be required. Then simply put the new injector in its place and secure it with the clip. Now with the new injector and new o-rings and seals in place, replace the fuel rail in the reverse of removal. Double-check everything and start the vehicle, keeping your eye out for leaks.
