Some mornings when I start the truck and it is cold she runs like absolute crap, others when it is equally as cold she runs like new. This has been the pattern for about 2 months. A month ago I replaced the plugs and she is running better but still rough and with a slight knock or tick. Today I filled her with half a tank of gas that was pure gas not 10% ethanol like I usually give her. The truck ran very well and even tho there was a slight knock it was much quieter. The noise makes its self more present around 2,000 rpm under that you can barely hear it. I don't know how to describe the noise but its there and quite annoying.