A vehicle operator should start service or repair work on fuel injectors by unscrewing the fuel filler cap so vapor pressure in the Fuel Tank decreases. The pcv clean air tube should be detached from the air inlet duct before removing the resonator and air inlet duct from the Throttle Body. Disconnect the central sequential fuel injection (CSFI) fuel metering body electrical connector while you detach the Brake Booster Vacuum Hose along with its connector from the Intake Manifold. Disconnect Spark Plug Wires from Distributor Cap cylinders 1, 3, and 5 while removing the Intake Manifold fuel line bolt at its rear position. The technician should first depressurize the fuel system before unthreading the nuts and clamp from the fuel pipe while checking the correct placement of the fuel pipe o-rings and washers and spacers. Begin installing the j 44466-12 and j 44466-13 to the metering body before tightening the hardware, then move onto hooking up the j 44466-11 and clamp followed by the j 44466-13 to the fuel pipe connection point. Place the j 41413 instrument on the tank valve to close it while discarding the regulator assembly and installing the j 44466-10 hose to the j 41413 tank. Ensure the metering body electrical connector receives connections from the j 39021, j 39021-210, and j 39021-301 while using the j 39021 amperage selector switch to set an output of 0.5 amps. Turn on the valves at the tank and j 44466-10 to build up fuel system pressure before maintaining at least 150 psi minimum pressure. Check that each injector operates properly by using the j 39021 as you observe the pressure drops. Stop the pressure flow at the j 41413 tank through its pressure valve and release all pressure at the j 44466-10. Install the pcv fresh air tube while disconnecting the j 44466-10 from j 44466-12 and j 41413 and removing j 39021-301, j 39021-210, j 39021 from the metering body. Proceed with connecting the electrical connector first followed by attaching the Brake Booster Vacuum Hose before reconnecting ignition wires. Secure the resonator and air intake duct before obtaining the j 38500-a which requires closure of the canister valve at its bottom. Place top engine cleaner gm p/n 12346535 into the canister before filling it with regular unleaded gasoline then suspend the j 38500-a. Insert the hose from j 38500-a into the service port of j 44466-12. Open the bottom valve of j 38500-a and establish shop air delivery at 75 psi. Follow these steps: make the j 38500-a empty while the vehicle runs then stop shop air delivery and allow the j 38500-a pressure to decrease. Disconnect the hose from the j 44466-12 before performing another pcv clean air tube, resonator, and ignition wires removal. After bleaching j 44466-12 of residual pressure, workers must remove j 44466-13 and j 44466-12 from the metering body before installing j 44466-13 followed by the clamp and j 44466-11 onto the fuel pipe. Lock and tighten the fuel pipe to the metering body using both clamp and nuts at 3 n.m (27 lb ft). Threadlock gm p/n 12345382 must be applied to the fuel pipe bolt before tightening it to 6 n.m (53 lb ft). The service continues with installation of ignition wires after fitting the Brake Booster Vacuum Hose and the resonator and the pcv clean air tube. A proportionate amount of port Fuel Injector cleaner from gm p/n 12345515 in canada must be added to each standard gallon of gasoline present inside the Fuel Tank. Put on the Fuel Tank filler cap and start the engine then inspect for leakage at the Fuel Tank. Use a tech ii scan tool to verify that powertrain dtc codes are stored and clear them if required before ensuring the customer switches to new fuel brands.