High pressure fuel pump strange behavior

[Eng_Ahmad1986]

Hello to all, as u can see in this video, the high pressure fuel pump operates intermittently, however the car idles smoothly, RPM steady, there are no engine vibrations, no loss of performance, no warning lights, car drives greatly, it should be noted also that if I turn the AC on or engage D or R , or if the radiator fan licks in , the pump operates normally !!

it wasn’t like this before , any ideas ?