Toyota p0504 puls not show on fuel injectors

The Toyota Tacoma has a fuel injector that mixes fuel with air. This technology almost completely replaced in the late 1980s and its programmable firmware allows the same hardware to be used with different fuels. A fuel injector is only a nozzle and a valve; it still requires a pump to inject the fuel into the engine.

• Determine which fuel injector your Toyota Tacoma will need. This depends not only on the make and model, but also the engine size. Models made before 2005 may have a 2.4L, 2.7L or 3.4L engine. The current version may have a 2.7L or 4.0L engine.
• Relieve the fuel system pressure and disconnect the negative battery cable with a socket wrench. Remove the engine under cover subassembly and drain the engine coolant. Detach the intake air connector and disconnect the throttle body motor assembly with a socket wrench.
• Disconnect the fuel lines and remove the fuel pressure pulsation damper assembly with a socket wrench. Unplug the electrical connectors for the fuel and vacuum switching valve. Remove the engine wiring harness clamp and the air conditioning compressor clutch connector with a socket wrench.
• Remove the two fuel rail mounting bolts with a socket wrench and lift out the fuel rail with the injectors still attached. Pull out the fuel injectors and discard the old gaskets.
• Use new gaskets and install the new fuel injectors by reversing the removal procedure.
• Fill the coolant reservoir with coolant of the proper grade and type. Start the engine and check for fuel leaks.

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there is a fuel control module at the pump that controls the injectors
have it checked out

run the fault codes
check fro broken timing belt/chain

I think I would be running the fault codes first to find exactly what is the problem. Missing is from fuel pressure and injectors or HT leads and coils and this will show up in the fault codes.. If you got water in the fuel then may be the filter is blocked so check that out.. If injectors show up it may be low fuel pressure in the manifold so have a pressure done there to check fuel pump/ pressure regulator and filter.

check for injector pulsation with a noid light if it dosnt puls suspect pcm but check all fuses first there is one for injectors

1) PO123 IS TPS throttle position sensor. this problem mean adjust in the voltage see the diagram use the VOM, in other model is self calibration by BCM.
2)P0504 SWITCH brake.

REPLACE THE FUEL INJECTOR CANT REBUILT IT.IF YOU REMOVE FUEL INJECTORS FUEL RAIL YOU HAVE TO REPLACE GROMMETS AND O RINGS ON ALL THE FUEL INJECTORS IF NOT YOU WILL HAVE A INTAKE LEAK AT THE OLD FUEL INJECTORS SEALS.REPLACE THE FUEL INJECTOR YOU REBUILT THEY HAVE TO BE REPLACED.

I believe it should be in the trunk under the carpet, it will have a round cap that removes for access.

follow your fuel lines back from the injectors/carb it is a cylinder shapped unit should be at the top of the engine near the windscreen

You HALL EFFECT SENSOR in the distributor controls both spark and fuel pulse---check there first for a defect (bad sensor/stripped distributor shaft).