YouI have an 07 F150 w/ the 5.4L triton. After the engine has reached operating temp it will knock and shake if it's at low rpm and I give it light gas pressure. e.g. crawling through a parking lot, crawling through traffic, pulling in to a parking stall etc. I see a lot of folks online having the same issue, but I have not heard of a sure fire fix. Just throwing money at it and nothing is resolved. Surely Ford knows what the issue is. Thoughts?