This topic is talked about ion almost every F-150 forum at length. This, along with a harsh 1-2 and 2-1 shift on the 6 speed auto transmission is a common complaint. I had the same issue on my FX4. I went through a PMC reflash twice. Ford says its normal....You will fight this until you are crazy. I say just drive it until you can't stand it. then take it in and have the PCM reflashed. Check the other forums. My only caution about reading forums is that you tend to draw yourself into the symptoms. Drive the truck and enjoy it, but that is always easier said when you are not behind the wheel, so I know how you feel. Been there....