gas pedal sticky

it seems like when im going 60 in 4th and drop it in to 3rd and floor it theres a lag in response. and its just me in the car no extra weight. Once i floor it theres like a 4 second lag till it picks up.
Does this matter or am i over reacting. I bought the car off a friend and have had problems with it from the start so im just trying to be sure.
Does this matter or am i over reacting. I bought the car off a friend and have had problems with it from the start so im just trying to be sure.