Yea its sucking air from the upper plenum. Take that black cover off that says 3.4 DOHC and with it running high idle squirt some brake clean along the plenum and you will hear and see it idle back down.
I have owned 3 of the Z34 luminas and 2 of the monte z34s with that engine and all but the last which was a 96 monte z34 i had to change the intake gaskets not due to leaking any coolant but for the condition you describe.
Alternators are another fun chore on those engines
Not to mention the oring for distributor plug off.