Hi
I agree with the other contributors. The symptoms you describe suggest either a lack of fuel or a lack of air. Has the vehicle been parked up for a period ?
Idling doesn't need much fuel or air, but as you rev up (especially under load) the demand for both goes up.
A lack of fuel could be due to insufficient common rail pressure, due to the HP pump not producing enough or a component allowing a considerable leakback. If the pressure drops too low with the engine running, the ECU will prevent injection, however this will trigger a warning and a fuel pressure fault code which you haven't reported. Also, this kind of fault tends to come on gradually rather than suddenly. Another possibility is a poor electrical connection to one or more injectors, especially if they have been sat in damp conditions. They take quite a high current so connections must be good.
A lack of air could be any kind of severe blockage/restriction in the air intake system, e.g. mouse chewed air filter or debris sucked in from this, collapsed hose ahead of the turbo, throttle body flap stuck closed. The air intake system is normally designed to avoid water being sucked into the engine but I guess it is still possible. The amount you report is rather a lot, and I can't immediaely think how it could have entered. You should be able to remove at least some of the large flexible air hoses and check what's going on. Follow the air circuit in sequence:
Air Intake
Air Filter
Mass Air Flow Sensor
Turbocharger (yes this spins fairly fast even at idle)
Intercooler (Heat Exchanger) Debris is unlikely to travel through the fine tubes in this
Motorised Throttle Body
Intake Manifold
The attached picture is the view looking at the rear of the engine.
