The duratec in my 99 SVT has been 'hesitant' to rev smoothly to higher rpms. It seems to be 'choking' as I'm gasing her. It doesn't happen everytime but when it does, it feels like I'm on a rocking horse. Having experienced just those few times is driving me nuts as I'm sure what's going on. Has anyone experienced this similar issue? Could it be the fuel pump?

Thank you in advance from a concerned newbie.