help with miss or power loss

[buck 01]

i have a 04 250 6.0 6 speed. When my truck gets to 1/2 tank of fuel it would miss when holding at a constent speed or when i let off peddle and get back on it like if some one was turning in front of me. when i filled it up it would stop and not do it again until fuel reched a 1/2 tank again. so i went to dealer and they replaced fuel fillters and checked it out but could not find anything. they put it on computer and check fuel pressure but not pressure going down road. two weeks later and now getting wores know its doing it when tank is full. No smoke runs fine under load climbing hills and at idel. now it even does it when i down shift and go to give it peddel it will hesitaet and then take off. and if i hold peddle it will buckjump until i let up on peddle or push on it. oil was changed about 2 thousand miles ago moter craft oil and filters. 70000 on truck. the guy at dealer test drove it but was driving it pretty had and on open road not in traffic or on back road all my drivin is on back roads and on farm i drive on highway very little. dealer said no codes. can some one help thanks

[Tuscany]

Sounds like the fuel pick up tube might be broken off and starving the injectors for fuel.