Toyota Land Cruiser Hardtop diesel cold start knocking and power loss(Requesting advice)
Hi all, I am looking for advice regarding a problem with my Toyota Land Cruiser Hardtop diesel that recently started developing an issue I cannot properly diagnose. The vehicle runs normally most of the time however on cold starts there is a noticeable knocking sound from the engine that is strongest in the first few minutes and then gradually becomes quieter after driving. I have also noticed a loss of power during acceleration and when climbing hills which feels more like hesitation than a full misfire. I have already checked engine oil coolant levels and air filter and everything appears normal. The vehicle had a recent service but the symptoms continue. There are no warning lights on the dashboard and no visible leaks underneath. I have considered possible causes including fuel delivery injectors or internal engine wear but I am trying not to guess or replace parts unnecessarily. I have even looked at sources such as local shops and online marketplaces like eBay RockAuto and Alibaba but still cannot narrow it down. This is my daily driver and I also use it for light off road work so reliability matters. What would be the most likely diagnosis in this case? Any advice will be highly appreciated.