Detail in operation of Honda Civic 2002 STD

Hello friends, I like to greet them again, I am writing to guide me about a detail that I have noticed lately in my Honda Civic (2002), Motor Manual Transmission OHV 1.7 VTEC.
In the last week I have noticed something peculiar by rapidly accelerating from the second speed, as it pushes normal and feels that it loses strength immediately later again brushing again as if a (turbo) Boost is activated that it does not have.
The engine works perfectly the air filter does not have much to change it (and clean it), the filter change service (gasoline, air, oil), spark plugs, oil does not have more than 20,000km that I did the owner manual says it is every 40,000km.
I hope and can guide me to detect the origin of this fault thank you very much.

The problem is in all marches or only in second? is that it can be from the obstructed escape to a flower problem, air hose or a coil in poor condition a little more detail