After reading some more of the posts here, I began to wonder if changing out my oil filter might not help. I took off the Fram PH3600 and replaced with Motorcraft FL400s, did not bother changing the oil as I wanted the filter to be the only difference. The engine was not completely cold, it had sat from 6pm to 11pm and was still a little warm (it's August in Mississippi here so still in the 80's late at night). To my surprise, the knocking was not there! I drove it around a few minutes and it was quiet. When I cranked it at 7:30am it was still quiet. I will give it a few days before I declare it fixed, I need to let it sit overnight without being cranked so it gets completely cold and then crank it, but it sure looks like my truck doesn't like Fram filters. I have tried different weight oils, additives, etc, trying to fix this, but I kept going with Fram filters each time. I guess all the advertising money they have spent worked well on me! I'll be sticking with Motorcraft or OEM from now on!