Hi, Most of the idle issues during neutral and park positions are due to a faulty IAC (or IAS as some say). This is the Idle Air Control device which controls how much air is taken in to the throttle body when throttle position is 0% This is operated through a PWM signal from the ECU. If the device is faulty it does not let enough air to reach the engine during idle then resulting an engine stall. You cannot adjust the IAC, hence need a replacement if it's faulty and not too expensive to replace. If IAC is working properly you here a faint hum near the throttle body Good luck with the diagnosis. Sent from my SM-G900F using Tapatalk