To perform the throttle body check, confirm that the throttle linkage moves without binding, engage the starter, disconnect each vacuum hose and check the vacuum with the gauge at each port on the throttle body at idle, and above idle and compare observations with accompanying tables. For replacement, first, ensure that the engine is fully cool then disconnect the cable from the negative terminal of the battery, and then unbolt the hose clamps and the air intake duct. Remove the accelerator cable from the throttle lever, remove the throttle cable bracket without disconnecting the throttle cable and further if this model comes with an automatic transmission then remove the throttle valve cable from the throttle linkage and then replace it. Using labels, disconnect all the vacuum and coolant hoses that are connected to the throttle body, disconnect the electrical connector of the TP sensor, unbolt the throttle body, and separate the throttle body along with its gasket from the intake manifold. Using a soft brush and aerosol carburetor cleaner, clean the inside and outside walls of the throttle body casting but do not clean the TPS. It is the process of taking off the throttle body and, in the process of doing that, make sure to over torque the mounting bolts of the throttle body as required. For the fuel pressure regulator, the fuel pressure has to be relieved, and the cable from the negative terminal of the battery has to be disconnected, followed by disconnecting the vacuum sensing hose from the regulator as well as placing a container under the fuel return hose. Twist the hose clamp to pull off the fuel return hose and for the four-cylinder engines, two regulator bolts need to be removed to remove the fuel rail. On 2.4L, 2.7L, and 3.4L engines, remove the pressure regulator mounting bolts, and disconnect the pressure regulator from the fuel rail, use a new O-ring when reinstalling the regulator. With regards to the Idle Air Control valve, one has to perform a resistance check across the terminals by shorting them. In case of need, unbolt the throttle body in order to gain access to the IAC valve, then, to separate it and put in a new gasket when reassembling. Regarding the fuel rail and the fuel injectors, first, close the supply of fuel to the injectors and then free the cable connection from the negative terminal of the battery, and lastly, unscrew the PCV hose. The fuel injector electrical connectors need to be disconnected and the vacuum sensing hose has to be disconnected along with the fuel rail with the injectors still fitted to it. If reusing injectors, then replace the grommets and O-rings. Another component that should be checked is a cold start injector, it is recommended to replace it if the resistance is higher, when replacing it, new sealing washers must be used. Another component associated with the cold start injector time switch is the check of the resistance in different temperatures of the switch and the replacement of the switch which has to be wrapped with Teflon sealing tape in each of its threads. Regarding the air intake plenum, the procedures include the removal of cable from the negative terminal of the battery, taking out electrical connectors, the removal of accelerator cable and transmission linkage, EGA pipe, vacuum lines, plenum retaining bolts and nuts. Before putting on the new gasket and air intake plenum assembly, one should clean and inspect this mounting surface and tighten the bolts to the proper torque.
Posted by ToyotaPartsDeal Specialist 
