Cummins QCB4.5 engine and electronic throttle pedal with an electronic fuel pump. It will start but idle cutting in and out and very low, at around 400rpm. No throttle response at all. All hydraulic functions will not kill the engine actual make the engine idle run smooth. Already swapped the pedal sensor, fuel filters lift pump, shut off solenoid and the only thing I could think of was the high-pressure pump, so I swapped that to and no change. I did time it right by what quick serv said. Also checked all the fuses, no codes coming up. Not sure where to go from here because I assumed a fault code would have popped up by now. I'm leaning towards ECM now but I'm not for sure. Any help
For all the people that have this issue. I have found that the is an intake pressure switch on the top of the intake manifold. There is two of them, on more in the middle of the intake manifold and one towards the rear of the intake manifold. Unplug the one towards the rear and you will gain all throttle and regain the idle back also. Replace this sensor and will run properly.