First of all A warm Welcome to the 4x4 Family
2ndly the engine oil & oil grade you are using is not good for 2KD-FTV
Recommendations: Liqui Moly 10W-40 or Cepsa Star Avant 10W-40
3rdly Diesel Knock
Recommendation: Use Quality Fuel & only use one pump I will recommend F-8 PSO, F-7 Shell or F-6 Shell
Before filling the tank use 2 Bottles of Liqui Moly Common Rail Additive... Full the tank.... and drive if the problem exists... Use Quarter liter ATF with Common Rail Additive in tank and full the diesel tank.... thats it....