[ultimateirving]

Ok if the bov is opening at idle and decel thats kinda a problem, if its adjustable tighten the spring a little it shouldnt be popping open unless your getting into boost.
Next the IACV is designed to catch the Rpm's on decel to keep it from stalling, It sounds like yours may be malfunctioning. Try cleaning it first, Remove it to clean and make sure you check the gasket before you replace it. Then search online how to set idle in SR20 because it is set thru the iacv