Well you said you've installed a new fuel pump so that shouldnt be the issue.

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Try checking the pressure on the rail, there should be a shrader type valve that you can check the pressure from with the right equipment.

If the pressure is reaching the rail ok then next port of call is injectors.

Fuel Pressure Regulators can give problems also

Once you've eliminated any mechanical fueling issues then its on to the electronics and Im not much use on them either to be honest