I have an F250 engine rebuilt 26000 miles ago. No if im in park and step on the gas i get a rotational vibration/ flutter noise, this also happens when im driving and stomp on the gas to pass or just speed up usually at higher rpm. However it will pass and be fine. i am mechanically inclined i cant figure it out neither can my mechanic i seems to think that its the fly wheel backing out. I replaced the drive shaft and u joints already. please help i am currently in iraq deployed and will be pulling my wifes 07 f 150 to colorado in april for post transfer and would like my truck to make it there. thanks SGT Hert