So a few months ago I made my own catch can which intercepts the PCV system, and basically acts like a big filter. A tube runs from the PCV valve on the passenger valve cover, to the can, and then out of the can to the plenum. The plenum tube has an enormous amount of vacuum on it. I noticed that there was a leak coming from the tube that connected to the PCV valve (which remember is under vacuum because it is connected to the plenum). I pulled the tube off and plugged it with my finger, and there was no more hissing. As soon as I put the tube back onto the PCV valve, the hissing came back and so did my low and stumbly idle. I tried tubes that were made with different materials, different clamps, and I even went and bought a new PCV valve because I thought mine was broken. As of right now I have a tube that runs from the PCV valve to the catch can, and the other side of the can is open to 'vent.' I put a small cap on the tube on the plenum. If you watch the video you can hear and see what I am talking about. Does anyone have any advice as to how to fix this issue...?

 

They will hiss simply from vacuum pressure drawn through a small hole. Are you sure its actually sucking atmospheric air though? You should try an idle air recal and see if it fixes the stumbly idle because I dont think thats the problem.

 

I can't remember if the pcv presses into the valve cover through some grommet or threads in but seems like that's the only seal you haven't replaced. or the valve cover has an air leak. a mechanics stethoscope helps when looking for stuff like this as you'll hear a big difference when you get the tip right near the leak.

i'm curious where you'll mount your can. i have a can just like that and it's mounted pretty hoopty at the moment because i'm not good at fabricating brackets and relocating things.

 

I plugged my little OBDII scanner in and it actually showed a P0507. I cleared it and it hasn't returned yet. Since I plugged the port on the plenum I noticed that my idle is now ~700 instead of barely above 5. It's been that low pretty much since I've had the car.

The PCV valve screws into the VC and has a large rubber o-ring on it. Since I got a new valve I know the seal is good.

As far as mounting the can, I have a whole thread and how I made it actually function and the bracket I made to mount it. Here is a picture for reference, but if you CLICK MEEEE you can view the whole thread.

 

ur car shouldnt be idling that low even if thats how it always was