Slow at thmes in building up power, almost lazy

When driving especially up a slight incline these is a marbling sound was described to me by someone as "pinking" and it moves lazy but gradually builds up power and then works great in mid stride it works well but at times is sluggish when moving off, I was told that the timing is off if so, how can this be rectified. Can I do it or is this the job for a mechanic