I have a 2004 F250 with the 6.0 diesel turbo. Had a wire chaff issue on a harness a short while back which I resolved which had created a bunch of codes. Got this all clear and after a couple of weeks of running well, it has started to lose power after 30 minutes or so of towing a 12ft enclosed trailer with 1500lbs in it. It acts like the turbo is not working. After sitting for a few hours and cooling off, it feels strong starting out but has the same issue in 30 minutes or so. No codes at all. I am baffled, but I am easily baffled! Any thoughts or suggestions would be appreciated.

 

Maybe the Vgt is sticking

 

Could be tired hpop. When cool oil is thicker, gets hot, oil thins, pressure drops. You must check deeper and report what you have

 

When was the last time you changed your oil?