Nissan Suny problem

Well, in a Nissan Suny the problem is the following, for some week I have been noticing that when I go in 5 and advance sometimes I notice lack of strength and pulls which when lifting the accelerator and accelerating again responds correctly.
Yesterday I started hitting myself sharply in all brands,

I looked at the catalyst if it is stuck, discarded
current-spark plugs have tough spark.
The filter are changed two months ago.

What can be
the engine is a 1.6 16v year 93

The fuel pump was checked, more or less at what speed it makes you fail, you cleaned the flijometro?, Check the TPS if it is in any of its paths.