Please help diagnose engine noise

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Sep 18, 2013 | 05:56 PM

Fatstrat

Thread Starter

Junior User

Joined: Mar 2004

Posts: 73

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Please help diagnose engine noise

My 2001 F-150 w/4.6 was coding a bad EGR. Took it off and cleaned it. Engine light gone. But now I have a strange hummimg sound that occurs only when RPM are dropping. As in coming up to a stop. Usually only lasts a few seconds. But occasionally as long as 30 seconds. Any ideas?

Sep 22, 2013 | 06:56 AM

enriched&beyound

Fleet Mechanic

Joined: Aug 2008

Posts: 1,446

Likes: 9

From: NE Iowa JD Country

Quote:

Originally Posted by Fatstrat

Hard saying....but taking a stab at it.... it might be that the IAC needs cleaning as well, can't hurt. Best way to clean the IAC is to remove the throttle body housing ( the IAC will come with it, note the condition of the PCV elbow as well), and clean the whole housing and then remove the IAC ac clean it. There is 2 EGR ports inside that can get pretty clogged up too.

..or you got a leak from cleaning the EGR??