2001 discovery TD5 engine cut off help needed

Its started a week ago, while climbing a seep hill at the desert, the engine was cut off like the fuel ended.
Closing the switch and restart the engine, it start immediately with no hesitation, no pedal was needed.
while driving a steep slope down, no issue with engine, all is well.
Drove home for 100KM up and down on the roads, no problem occurred, normal gear change and top RPM for gear change was 4200RPM as normal from my 7 years experience with this car.

I can reproduce the cut-off each time I step on a high rock with my front left wheel, then the engine cut-off, doing the same with the front right wheel the scenario does NOT happen
Driving fast in the round-about fast enough (Left hand side driver) the car gets a big roll over to the right, the engine cuts off.

So I have two actions help me reproduce this engine cut-off:
1. Climbing a large rock with front left wheel.
2. Driving fast in a round-about.

I had some suspicious with the following:
1. Genuine Fuel filter - was replaced- symptom 1 was happening, symptom 1 was happening.
2. Replaced fuel pump - OEM Bearmach - symptom 1 was happening, symptom 2 was gone.
3. Bypass the Interia switch - symptom 1 was happening, symptom 1 was happening.

Maybe Fuel Pressure regulator?
Electric issue?