not a vacuum leak?

[5-point-oh]

my vacuum system has been giving me problems and running sluggish lately. my idle is fine until my engine gets hot(which is another problem due to this) i've replaced my pvc, hoses that connect to throttle body/manifold/firewall and my connectors/tee. and i dont neccesarily hear a leak anymore. but the lack of performance is still there and i hear a discharge of air when i turn my motor off, can there be a clog/restriction somewhere else? i saw, i guess, a regulator thats seperating the hose from a box that sets near where my radiator bleeds out. im thinking this is the problem. any suggestions?

1986 GT.TYPHOON Manifold and 75mm Throttle body by Professional products. MAC cool air kit. Full MSD Ignition+6a. Subframe connectors. Pullies. Full Monroe Suspension tuned for Street handling. Brake upgrade to 73mm calipers/11'' rotors. Short shifter BBK shift knob. 19lb fuel injectors. flex-a-lite Flex Fan(soon to be electric). MAC Headers. H-pipe. 2 1/2 flowmasters dump at axle. BBK 170 mph speedometer. 245/45/17 Front. 275/40/17 Rear. no a/c or smog.