The first thing I'd do is see if the ECU is recognising the throttle input. That's easy - any mechanical workshop will have a diagnostic tool that can be used to read this but you can also put a Bluetooth OBD2 adapter (ELM327) in the OBD port and use an Android app like "Torque" to read the throttle info.
If there's no change when the throttle is depressed, the ECU isn't getting the signal so it's time to look at the connector on the throttle pedal. If it IS getting the signal then it might be the throttle body. It's unlikely to be the pump because it's idling and of course the pump has to deliver fuel to do that (at about 4,500psi).
