Dear customer, these types of failures are common with the time and travel that your vehicle has, identify them accurately is hard but I will proceed to indicate the areas that you should check in your vehicle so that you understand what is happening and we can reach the solution of your problem
A diesel vehicle works with certain conditions that we must have in full operation so that the vehicle works well
A diesel vehicle requires the following 4 factors
1) good compression in the cylinders
2) a high pressure in the fuel injection system
3) a good air intake
4) and a high temperature in the cylinders.
Firstly, the compression can be rule out in your case, because when there is a loss of compression in the cylinders, the vehicle constantly fails more in the Diesel, so do not worry because this happens when there is internal damage to the engine but it is not your case.
As a second, you can have problems in the fuel injection pressure, this pressure is given by the fuel pump, but there are certain factors that can affect this pressure, such as lack of maintenance, dirt in the tank, filters clogged or dirty, a defect with the injectors cause these problems as you describe me, for example your vehicle is in good working conditions until the pump becomes clogged with dirt or overheats more than usual causing it to lose strength and cause your failures
This is solvable by performing maintenance on the fuel rail and its components, in addition, replacing its filters.
Then as I mentioned a good air intake is necessary for a good operation of the vehicle, when we present problems in the air supercharger/ air intake or in some sensor of the throttle body or mass air flow, because these sensors are responsible for regulating the acceleration of the vehicle, to know the good or bad operation of these is necessary to perform a computerized diagnosis to know the parameter of them.
At last a good temperature, if the faults occur in very cold climates, it is good to analyze the refrigeration system and thermostat of the vehicle, if the engine cools more than the account also produces power losses.
As you will see dear customer there are several factors to analyze, I consider it prudent that the first thing you do is a good automotive diagnosis with a scanner that has Hyundai software according to the parameters that the technician obtains, we proceed to check.
Another case that we have to take into account is a deprogramming in the system, but with the diagnostic scanner it will be easily rule out or sorted out, this is done resetting the data to factory and it generally solve the problem.
Dear customer, this are the causes we need to check in order to have the problem sorted.
Have you understood me, dear customer?