How do you replace the fuel injector o-rings on a 1991 Nissan Stanza?

To replace the fuel injector o-rings on a 1991 Nissan Stanza, first, relieve the fuel system pressure by removing the fuel pump fuse and starting the engine until it stalls. Next, disconnect the fuel lines and electrical connectors from the fuel injectors, then remove the intake manifold if necessary for access. Carefully pull the fuel injectors out, replace the old o-rings with new ones, lubricate the new o-rings with engine oil, and reassemble everything by reversing the disassembly steps. Ensure all connections are secure and check for leaks after reassembly.