Hissing sound from engine when accelerating lightly
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Hissing sound from engine when accelerating lightly
I have a 2006 5.4 3 valve and over the past two or three months it started making a hissing sound during light acceleration or holding the accelerator down to keep speed when it makes the hissing sound you can feel a loss of power once the hissing stop the power comes back it does it off and on has nothing to do with air conditioner there is zero freon in it and the compressor is unplugged the hissing sound sounds like it's coming from the intake manifold it does the hissing intermittently only for a few seconds then goes away does this off and on about every 10 to 20 minutes sometimes more frequently when you shut the vehicle off you can hear the same hissing sound any help would be much appreciated I am baffled oh also at an idle does not make the hissing sound but it is running slightly rough at an idle but not extremely noticeable it fires right up has never stalled but I did get a lean code once about a month ago but not since
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When doing the unlit torch test it doesn't hurt to have the truck hooked to a scanner that can display live data and keep your eyes on the fuel trims,and when they go crazy you've found your leak. A lot of times if you're not hooked to a scanner the computer will react so fast the idle won't change, and you'll miss the leak.
#6
When doing the unlit torch test it doesn't hurt to have the truck hooked to a scanner that can display live data and keep your eyes on the fuel trims,and when they go crazy you've found your leak. A lot of times if you're not hooked to a scanner the computer will react so fast the idle won't change, and you'll miss the leak.
included as a screenshot of everything that I can check with my setup at idle does everything look in range?
Last edited by mustang427; 01-18-2019 at 11:53 AM.
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