I have a 2001 honda with about 49,000 miles on it.
It's a 4 cyl car.
I have had this problem for several years now.
When the car accelerates from idle, it feels as if
someone hit it from behind. It does not accelerate
smoothly, rather it feels like it has been knocked from
the back. So it accelerates rather abruptly.
There is no shaking and engine runs well otherwise.
The engine never dies.
Should I try the fuel additives. I had the throttle body
You talk about adding additives but you haven't stated that the car makes a slight hesitation before it takes off. Would you say that was true? What is the the idle rpm? It might possibly be a failing plug wire.