Dies while idling, LOUD humming noise between 1k-2k RPM

kilahcin

New Member
Aug 12, 2011
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My wife bought a 2000 GT and everything was great until... we went on vacation for a week and when we got back it started making a loud humming noise when you'd start the car up ... all the way up into about 1.9-2k RPM.

I have

Cleaned the MAF (didn't appear to be dirty)
Replaced a bunch of tubing that was cracked and soft
Cleaned the IAC (or at least I thought I did)
used some throttlebody cleaner on the intake with a toothbrush

There is no check engine light... took it to oreillys and there were no codes.

I have not

Replaced the IAC
Looked at the intake manifold (not even sure what to look for here)

I have noticed that if I take off the baffle that connects to the IAC (this one: Little black box. What is this part?? - Modular Depot Forums) that the whining appears to go away. :shrug:

Any other advice?
 
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My recommendation is to replace the IAC and PCV valve. The noise could be the PCV value almost as easily as the IAC.

The square box is a resonator. It's purpose is to act as a muffler to decrease the sound of air passing through the bypass line.

Somebody will chime in to tell you not to clean the inside of the stock TB. There's a coating on it.

IMO, it's not possible to tell if a MAF is dirty by looking at it.

Here's some more information on the IAC:
Is your mustang stumbling, dieing at idle or idling rough? - Page 14 - Ford Mustang Forums
 
I actually have replaced the PCV valve.

Will look over the link you posted. Thanks!

You need to also consider that your Throw-out Bearing, it whines sometimes as well. My stock throw-out bearing; chirped, whined, and rattled.

If it is RPM related, consider it is a rotating mechanical issue.

From my experience PCV valves will start to chirp because of excess oil above the spring in check-valve.

FYI, cleaning the IAC is just buying you very "minimal" time, if it is the issue then you will; sooner then later, have to replace the IAC.

The motor adjusting the amount of air in the IAC does make an audible amount of noise.
 
All Fixed

Went to Autozone and pulled the electrical connection off the IAC.... nothing changed. So I bought and replaced the IAC with the $52 option from autozone... so far the noise is completely gone and I haven't had die on my while idling since. Thanks wmburns! :hail2: