Toyota Auris, 2007, D4D(1ND-TV)-Diesel-P0191 fuel rail pressure sensor circuit

Hi. Can you guys give me an advice?
Toyota Auris, 2007, D4D(1ND-TV) diesel, 111000 KM.
Customer complaint is: Engine loses power, sometimes and MIL on.
DTC:P0191 fuel rail pressure sensor circuit range/performance
I took out my China scope and I probe signal from rail sensor and rail fuel pressure regulator.
Activation wafeform for fuel pressure regulator has an anomaly (check attachment) and i dont know what can it be.
It is possible to be a bad ECU driver?
Fuel rail pressure sensor signal looks good all time, so I dont think it is a problem with the sensor
Can anybodie point me in the right direction with this diagnosis?

Thank you.

The fuel rail pressure regulator is PWM controlled so relatively immune to minor voltage fluctuations. It is more likely you are looking at a pressure sensor or associated wiring issue. The usual osiloscope test for a fuel rail pressure sensor performance is s snap throttle test. For this test you need a screen that covers a full 10 seconds or so. On.a fully warm engine from key on engine off start and allow the engine to idle for a couple of seconds then snap throttle to near max rpm and back to iidle for a few seconds then key off.

This is for a Bosch system but it should be similar