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The only right way to do this job is to take them out and take them to a machine shop. Have the injectors blue printed and balanced. That would be right only right way to do this.
You can buy some products such as sea foam and run it through the gas and that will clean the injectors. However if you want it done right, take them out and have a shop blueprint and balance them.
Relieve the fuel system pressure as described in this section.
Disconnect the negative battery cable.
Wrap the connection with a shop towel and disconnect the high pressure fuel line at the fuel rail.
Observe all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion.
Remove or disconnect the following:
Positive Crankcase Ventilation (PCV) hose
Exhaust Gas Recirculation (EGR) solenoid valve connector
Manifold Differential Pressure (MDP) sensor connector
Purge control solenoid valve connector
Throttle Position (TP) sensor connector
Idle Air Control (IAC) motor connector
Electrical connector from each injector, label for reference
High pressure fuel hose
Fuel return hose
Fuel pressure regulator
Fuel return pipe
Bolt(s) holding the fuel rail to the manifold. Carefully lift the rail up and remove it with the injectors attached. Take great care not to drop an injector. Place the rail and injectors in a safe location on the workbench; protect the tips of the injectors from dirt and/or impact.
Injector insulators from the intake manifold, discard. The insulators are not reusable.
Injectors from the fuel rail by pulling gently in a straight outward motion. Make certain the grommet and O-ring come off with the injector.
Fuel injectors and related components-Lancer 2.0L engine
Install a new insulator in each injector port in the manifold.
Remove the old grommet and O-ring from each injector. Install a new grommet and O-ring; coat the O-ring lightly with clean, thin oil.
If the fuel pressure regulator was removed, replace the O-ring with a new one and coat it lightly with clean, thin oil. Insert the regulator straight into the rail, then check that it can be rotated freely. If it does not rotate smoothly, remove it and inspect the O-ring for deformation or jamming. When properly installed, align the mounting holes and tighten the retaining bolts to 84 inch lbs. (9 Nm). This procedure must be followed even if the fuel rail was not removed.
Install or connect the following:
Injector into the fuel rail, constantly turning the injector left and right during installation. When fully installed, the injector should still turn freely in the rail. If it does not, remove the injector and inspect the O-ring for deformation or damage.
Fuel rail and injectors to the engine. Make certain that each injector fits correctly into its port and that the rubber insulators for the fuel rail mounts are in position.
Fuel return pipe and fuel hose
Fuel return hose to the fuel rail
High pressure fuel line to the fuel rail
Fuel injector connectors
IAC motor connector
TP sensor connector
Purge control solenoid connector
MDP sensor connector
EGR solenoid valve connector
PCV hose connector
Negative battery cable
Pressurize the fuel system and inspect all connections for leaks.