Why is my car doing this!? *video*
02-02-2010, 06:46 PM
#1
5th Gear Member
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Join Date: Jan 2006
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Why is my car doing this!? *video*
this car is driving me crazy right about now. recently it has been making this fluttering noise from the intake. during these "episodes" at idle the rpms go up to 1500 but it happens while i'm cruising too. its a pain in the *** in stop and go traffic because the car wants to accelerate while its happening. any ideas on what's causing this?
http://s117.photobucket.com/albums/o...2022010056.flv
http://s117.photobucket.com/albums/o...2022010056.flv
02-03-2010, 03:41 AM
#3
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
I had a mysterious sort of honking/snorting sound late last year that I tracked down to the IAC by using a mechanics stethescope--it was sticking and vibrating and the intake tube and air box were behaving as a horn, amplifying the sound.
A new IAC valve fixed it up.
A new IAC valve fixed it up.
02-03-2010, 09:20 PM
#4
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yea Cliff that's what i'm thinking too. i tried cleaning it today because the car actually stalled on me but now its worse! its almost impossible to drive in traffic. i'll get a new IAC and let you guys know
02-03-2010, 10:00 PM
#5
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Join Date: Dec 2006
Location: Saint Augustine, FL
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The plain ol' at idle IAC control signal looks like this:
When tracking down the "honking" noise I had I was somewhat surprised to find it was a 2.1kHz signal--don't know why but I had expected it to be a lower frequency. In any event it was obviously a harmonic of this that was makeing the "honk" I heard. I suspect your noise may be the same source but with different fundamental and harmonic resonances at work...
When tracking down the "honking" noise I had I was somewhat surprised to find it was a 2.1kHz signal--don't know why but I had expected it to be a lower frequency. In any event it was obviously a harmonic of this that was makeing the "honk" I heard. I suspect your noise may be the same source but with different fundamental and harmonic resonances at work...
02-04-2010, 09:04 PM
#6
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Join Date: Aug 2008
Location: Seymour Johnson AFB, NC
Posts: 445
this car is driving me crazy right about now. recently it has been making this fluttering noise from the intake. during these "episodes" at idle the rpms go up to 1500 but it happens while i'm cruising too. its a pain in the *** in stop and go traffic because the car wants to accelerate while its happening. any ideas on what's causing this?
Last edited by Pohatu18; 02-12-2010 at 04:56 PM.
02-12-2010, 05:45 PM
#8
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Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
Way Cool...
99.44% of idle issues are IAC related (mostly because it's the only thing that controls the idle) but for some reason many want to go off on all sorts of other adventures rather than just buy a new IAC.
Ford states in the shop manual, in no unambiguous terms, that it cannot be cleaned and must be replaced if malfunctioning--this also seems to be an unpopular 1st step?
99.44% of idle issues are IAC related (mostly because it's the only thing that controls the idle) but for some reason many want to go off on all sorts of other adventures rather than just buy a new IAC.
Ford states in the shop manual, in no unambiguous terms, that it cannot be cleaned and must be replaced if malfunctioning--this also seems to be an unpopular 1st step?
Last edited by cliffyk; 02-13-2010 at 10:14 AM.
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