Hi this is my first post on Diesel Place. I recently purchased a 2003 Silverado Duramax. The engine has 130000 miles on it. It appears the previous owner did a good job as far as service goes. The truck never had a tune on it. I have all the service documents and when I replaced the injectors the internals of the engine was spotless. I replaced the injectors not long after I bought the truck due to the haze coming out of the exhaust as well as mileage on the truck with original injectors. The problem came after I replaced the injectors. The engine developed a knock ranging from a tick to very noticeable and annoying while driving on the highway. I recently borrowed a friends EFI Live and discovered the knock was coming from the #8 cylinder. What is most likely to create this knock? I am trying to determine if the most probable cause would maybe be the copper washer not sealing properly (cup was very clean when injector was installed). Or maybe injector failure or etc. I have another injector on the way but if someone could tell me it is most likely not the injector and to look at something else I would consider this before buying the injector. The engine did not knock prior to changing injectors.