My truck sputters when driving when I hit 45mph it shift into last gear and starts shaking the more I press on the pedal the more it shakes but when I press hard it down shifts and goes away til it shift back to last gear. I've changed spark plugs and wires/ coil pack.

 

Year and engine?

Brands of spark plugs/wires/coil pack?

 

Classic example of a faulty coil.
Good luck.

 

99 5.4L spark plugs are nkg and coil packs not sure.

 

Should always use Motorcraft coils. Your truck acts like it has a bad coil to me. Some off brand coils can be bad out of the box.

 

Yes, use MC plugs and coils.

 

Motorcraft plugs and Motorcraft, Denso, or Delphi coils.

40 bucks for a set of coils? What do you expect? They are junk.

 

yep, junk coils