After startup, the engine runs very high (around 3500 rpms) while idling. After several startups, with the same result, no engine trouble codes popped up. Problem was the Idle Air Control (IAC) valve. Carbon deposits had caused the valve to stick in the open position, allowing too much intake air. The vehicle's ECU could not control the IAC valve to run at the proper idle speed. This condition can happen to a 2001, 2002, 2003, 2004, 2005, 2006, 2007 and 2008 Escapes, Tributes and Mariners. After 2008, Escapes went to an "electronic" throttle body, negating the need for an IAC valve.
