Why the engine vibrates hard and the car hesitates when accelerating at higher speeds

What is your question?

The hesitation does not happen from a stopped position, only when accelerating while going down the road at higher speeds, and the engine sounds like it's being held back.

What makes this problem better or worse?

It gets better when you let off of the accelerator.

How long has your 2010 Volvo S40 had this problem?

Just recently