Have a slight idle surge or hunt of about 200-500 RPMs at hot idle. Hot Idle set at around 1000 RPMs. The idle smooths out when I disconnect the o2 sensor. The sensor is a brand new bosch one wire universal. The old one had been disconnected by PO and never noticed. I've done away with the Bosch AAV and installed a man op one, If that makes a difference. Also replaced hoses in the eng compartment. ??????? Thanks in advance for your help!