Hello. well like the title says I've been having a hesitation/sputtering when under load/driven as if the vtec kicks on at times while in between 2500-4000 rpm. The funny thing is that it never does it while revving while parked. anyone have any idea? Its driving me nuts.

 

any cel, most likely your misfiring like crazy!

 

Inspect the plugs, wires, cap, and rotor and check the ignition timing.