is vtec even wired up? sounds like they swapped in the z6 and just plugged in the non vtec wiring harness with the non vtec ecu. the p06 will run that engine, but with those exact symptoms.
is your iacv wire three wires or two? if it is three wires then you will need to do the three wire to two wire iacv conversion. there is a writeup on that somewhere around here, or honda-tech i believe.
sounds dumb, but is your vtec solenoid and pressure switch even wired to the ecu?
i dont know about the z6, considering i have y8, but if then engine was automatic, and i believe nonvtec it will come with a three wire iacv