How do you change a fuel injector for a 2004 Chevrolet trailblazer?

To change a fuel injector on a 2004 Chevrolet Trailblazer, first, relieve the fuel system pressure by removing the fuel pump fuse and running the engine until it stalls. Next, disconnect the battery, remove the intake manifold, and access the fuel rail. Detach the fuel rail from the injectors, replace the old injector with a new one, and reassemble everything in reverse order, ensuring all connections are secure before reconnecting the battery and starting the engine. Always consult a repair manual for specific torque specifications and procedures.