vehicle- 93 dakota reg 4x4 auto v6 180k

My truck in the past couple of months has been making a hissing/breathing sound or like my engine is exhaling around where the IAC sits. Also on every other start up my truck will shake and sometimes almost stalls. Today I notice the IAC fault code showed up on my OBD computer and so I replaced it. The new IAC didn't make a difference. I noticed that where the PCV hose line connects to the combustion chamber it's been making a buzzing sound through the hose.

So far I replace my throttle body gasket, EGR valve, PCV, IAC, and some vacuum lines in the past 10 months.

What could be the problem?

Thanks

 

The IAC are very problematic. Even new are faulty quite often. So you could have gotten a bad IAC or you have a wire problem. Since you have a code the computer is telling you there is a problem in that circuit.

The IAC can make the hissing sound. It is normal. The PCV do make a rattling sound due to it working.

 

I was able to erase the IAC code and I believe the only reason that code appeared is because I got the IAC wet from throttle body cleaner yesterday. I know the PCV rattles but what I meant is the hose is vibrating like a hand massager and makes a weird buzzing sound that's pretty loud. My engine is rumbling and shaking on every other start but once I start to accelerate it runs smooth and doesn't do anything until the next start up.