GM-GMC: wrong fuel in 6.5 diesel, diesel fuel, full tank

Question
i had 20 liters of diesel and the pump person put 40 liters of gas in the tank. I filled it up to the top with diesel added some and drove 200km.I then put more diesel in and drove 100km continued doing this now i still have rough start and a small knock in the engine. Did I do damage to the engine? I have since put a full tank through the engine and it seems to be getting better but with a small knock still in the engine. Is this a fuel knock?

Answer
Perhaps you had no other choice, but you should not have driven the vehicle with 2/3 of the fuel being gasoline.

Gasoline is a solvent and your vehicle's fuel system is designed for an oil (albeit a light oil known as diesel fuel).  The engine ran hotter than normal on the gasoline and the injection pump and injectors did not receive proper lubrication.

Your noise may be a damaged injector.  If it is knocking at idle, loosen each injection line in turn to see if the knock goes away.  This will pinpoint the cylinder causing the knock and you can try changing the injector to see if it was the problem.