This is topic Loud air hiss from Intake in forum Tech Talk at Northern California Ford Owners  .


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Posted by Teddy Tiger (Member # 2473) on :
 
For the past couple weeks, I've been getting a louder than normal air hiss from my Intake. I've got a K&N Filter, but I took off the whole intake hose and still got the sound from just the upper plenum...any ideas? All of my hoses are okay. The engine idles rather high, too, like it's getting a little extra air from somewhere...

Nick
 
Posted by mike g (Member # 2919) on :
 
check for vacuum leaks...
 
Posted by KCmustangboy (Member # 1927) on :
 
quote:
Originally posted by mike g:
check for vacuum leaks...
what he said! [patriot]
 
Posted by Teddy Tiger (Member # 2473) on :
 
quote:
Originally posted by Teddy Tiger:
All of my hoses are okay. The engine idles rather high, too, like it's getting a little extra air from somewhere...

Nick
Like I posted before, all of my vacuum hoses are okay. I even had a Ford tech take a listen and look, he verified the hoses are okay. Someone mentioned that the paper gaskets could get sucked in from the Upper plenum, or that the IAB motor could be sticking...

Nick
 
Posted by cobraman_1994 (Member # 467) on :
 
did you accidently install a vortech supercharger instead of a K&N air filter?
 
Posted by Luke87GT (Member # 21) on :
 
Get a vacuum gauge and check what your vacuum is at idle. If it is erratic, you got a vacuum leak most likely. Track it down.
Luke
 
Posted by wikdstang (Member # 357) on :
 
I have the same problem anyone know where i can get a vaccum diagram for a 2000 4.6?
 
Posted by Cobra5.0Jeep (Member # 1482) on :
 
Where is the noise coming from on the intake? get a hose and put it up to your hear and try and track down the noise.
 
Posted by Teddy Tiger (Member # 2473) on :
 
It sounds like it's *inside* the upper plenum...
What is weird is that when I let the clutch in, it idles very hight (1200 rpm) then after a few seconds will drop back down to 900rpm, almost like something might be sticking.

Nick
 
Posted by nitrousracing (Member # 1346) on :
 
I had the same problem with my 96 GT. It was coming from the upper plenum. It was the butterfly in the upper plenum that was not closing fully, it had some gunk on it. Try cleaning that. It went away for awhile then came back.

Also they are right could be a vacuum leak.
 




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