Front Exhaust Camshaft Valvetrain Howl?

[yzstud]

So, I went to start up my car yesterday morning and once it started i heard a loud pitched howl. The first thing i thought was lower end engine. So i grab my stethoscope to listen to the oil pan area and i hear nothing that sound like that i am hearing. Wow, what a relief. I then throw it on the front bank cat, and there is the noise i am looking for. I then get up and place it on the front exhaust manifold near the #6 cylinder and nothing, then the #5 and nothing, then i place it on the #4 and there is that noise again. So i then place it on the the #4 cylinder exhaust cam area under the valve cover and there is that noise again. What could possibly be making that howl on the #4 cylinder exhaust cam? A worn out shim? worn cam lobe?
if needed be, i could post a video of the noise, thanks in advance

 

[gurucomputers]

So, I went to start up my car yesterday morning and once it started i heard a loud pitched howl. The first thing i thought was lower end engine. So i grab my stethoscope to listen to the oil pan area and i hear nothing that sound like that i am hearing. Wow, what a relief. I then throw it on the front bank cat, and there is the noise i am looking for. I then get up and place it on the front exhaust manifold near the #6 cylinder and nothing, then the #5 and nothing, then i place it on the #4 and there is that noise again. So i then place it on the the #4 cylinder exhaust cam area under the valve cover and there is that noise again. What could possibly be making that howl on the #4 cylinder exhaust cam? A worn out shim? worn cam lobe?
if needed be, i could post a video of the noise, thanks in advance

I have a similar issue but goes away with a slight rise in RPM. However mine is comming from the airbox. Maybe the whine is the vaccume line running to the VC

 

[Danz13]

I have a similar issue but goes away with a slight rise in RPM. However mine is comming from the airbox. Maybe the whine is the vaccume line running to the VC

Your howl is coming from your IAC, sometimes cleaning it makes it go away. I had it on my atx, and tried to clean it with brake clean, and it messed it up. So I got a mtx one from the jy and no more howl