Probably the coil packs on the ignition system. When they begin to deteriorate, they first give problems when under a load/acceleration. Pull your codes and see if your computer has identified which cylinder is fading.
I have an 04 F-150 Heritage that did something similar. I changed out my front and rear U-joints on the drive shaft and it worked. They cost $10 at autozone for my truck. Ford dealer wanted over $800.