IAC/Whinning noise/ECS leak

What is your question?

2003 Ford Escape due to failure to start without foot on the gas because of flooding out had IAC replaced at 32,000 miles again IAC replaced at 58,000 miles due to flooding out when started. 70,000 miles had throttle plate and air flow sensor cleaned and again at 91,000 miles. An inconsistent whinning noise occurs only at low speeds and only makes the noise when the tempertures are hot outside. On 4-2-11 Check engine light came on. Self diagonistic handheld instrument indicated emission control system leak-very small. Mechanics want to replace the IAC again. Whinning noise is so inconsistent that I have been unable to get it to a mechanic when it is occuring. Any ideas what can be going on? Thank you!