Mitsubishi ASX issue

Hello !

Mitsubishi ASX ( or RVR or Outlander Sport) owner, 2014, diesel, 4N14 engine code, automatic.
When temperature (outside) goes over 35 degree ©, the engine goes crazy.
This happened only at load, NOT when the car is stopped and only when rpm is between 1500-1800.
Big vibrations, rmp up and down (+/- 50 rmp), higher consumtion. If I will increase the rpm (shift in lower gear), the vibrations disapear. At idle, rpm stays still.
No engine light on, no errors on any system of the car.
Engine oil was changed regularly also the geabox oil was changed. EGR valve and throttle was cleaned. Fuel filter also was changed.
Does anyone have any ideea?

Thank you !

35C = 95F. Pretty darn hot in much of the world. Sorry, I don’t know how outside temperatures could affect a diesel. There are no heat sensitive ignition components!