To replace fuel injectors on V6 and V8 engines, begin by relieving the fuel system pressure, disconnecting the negative battery terminal, and removing the fuel supply line at the fuel rail. For V6 engines, removing the intake manifold and related components is necessary. Special fuel injector service tools are recommended for ease and safety. Remove the foam insulator, gasket, and the fuel pressure sensor. Disconnect the high-pressure fuel line from the pump and fuel rails. On earlier models, disconnect the fuel rail crossover line and replace it when removed. Remove the mounting bolts from both fuel rails, then evenly pry out the Bank 2 and Bank 1 fuel rails and injectors from the cylinder head. Disconnect the injector harness and remove retaining clips. Take care not to damage the injector grooves. Remove old combustion chamber Teflon sealing rings and upper O-rings from each injector, ensuring the grooves are clean. Install new Teflon seals using special tools or, without tools, slide them onto a socket and transfer them to the injectors, then use plastic tubing to shrink them back to the original size. Install support rings, lubricate upper O-rings with engine oil, and install them above the spacer. Clean injector bores and install compensation elements and retaining rings. Insert fuel injectors into the cylinder head, aligning them properly, and install spring steel retainers. Secure the fuel rail, reconnect the high-pressure fuel line, and reinstall the fuel pressure sensor. For V8 engines, remove the engine cover and disconnect the fuel supply line. On non-supercharged models, disconnect electrical connectors from each fuel injector. On supercharged models, disconnect main engine harness connectors, various sensor connectors, ignition coil connectors, and unclip the harness. Remove fuel rail fasteners, then the fuel rail assemblies, and disconnect electrical connectors from the injectors if not done earlier. Remove injector retaining clips and pull the injectors from the fuel rail. Remove old O-rings, replace them, and coat the new O-rings with engine oil before installing them on the injectors. Secure the injectors with retaining clips. Reconnect electrical connectors if disconnected earlier, and follow the reverse procedure for reinstallation. Finally, reconnect the battery cable and activate the fuel pump to check for fuel leaks in the lines, fuel rails, and injectors.
Posted by GMPartsGiant Specialist 
