Okay my daily driver is a 99 nissan altima. My inspection is due and my service eng' light on. I check it and it reads, idle air control circiut. So I buy the IAC valve take of the old one install the new one and now the car has a super high pitch whistle screaching from the new IAC valve. I tightend it real tight used the gasket put the hose clamps back and plugged in all connections. I think it might be a gasket problem but I dont know. Please I really need some help!!!!! TOM