miss under a load

When I "floor " it about 35 upto about70 I feel a miss .It is hard to explain. It reminds me of a carb. back in the days when it would almost backfire -or miss . I dont loose and speed it will contiue to gain but it "bucks" when i give it alot of gas. It seemd to run fine at other times .I have a 2002 with 4.6.

Thanks, CHRIS

I just worked on this problem with my 97; whenever I accelerated it would buck and I would hear a popping sound. It seemed that there was fuel burn in the cat so I checked the spark plugs and the looked white. Almost as if they were burning too hot so I replaced the plugs and spayed carb & choke clearer on the two elements in the inside of the mass air flow sensor. I gave the MAS about 2 hours to dry and once I did that everything started working correctly. Good Luck.