So when I turn my engine off I occasionally hear what sounds like my engine exhaling. Does anyone know what exactly is going on. I mean is it the egr, iac, or something else. It's a normal sound that I've heard since I bought the car just curious what is going on.

 

You sure it's exhaust? Anything else on the car

 

that sound is the vacuum pressure escaping from your intake manifold during shutdown, takes about 1-2 seconds

 

^^^^^bingo. completely normal

 

And it is especially more noticeable if you have an aftermarket intake, as the stock intake muffles this sound.

 

yea i noticed this alot more with a ram air intake

 

That's what I was thinking but it was almost 2am brain shut down

 

I had it on my turbo car, it was a vac on the driver side of the intake.

 

Haha mine sounds like its doing a sick kinda cough. Made my brother and me lol...

 

My aem cai makes the same noise on turnoff too, completely normal.

 

Yeah, my car does this as well.

However, just something to add. When my IACV was dirty and giving me some problems, it seemed that the engine was "exhaling" louder and more painfully. Maybe I was just being an automotive hypochondriac, but I figured I'd throw that out there.