I just noticed this the other day after Infiniti replaced the valve covers under warranty because of leaking gaskets. With the car at idle, it sounds like there is a vacuum leak on the passenger side of the engine. After narrowing it down, it is coming from the PCV valve on the passenger side valve cover. I dont ever remembering hearing the sound before, but it is definitely there now. Is this normal? Any of you guys with a Z or G noticed this? Anyone willing to start your car and check to see if you hear it? It sounds like it is pulling A LOT of air from the valve cover.

 

Did they replace the PCV valve when they did the valve covers?

According to the FSM you should be able to hear a hissing sound coming from the PCV when operating correctly.

I can hear mine.

Is your idle normal? If you're PCV valve hasn't been changed you might consider doing it. PM if you need a link to a service manual.

 

I doubt they replaced it. I decided to go and get a new one tonight, <$15 and 70k miles, it wont hurt.

Idle is normal, as in, it idles around 600 rpm. BUT, I can feel it almost missing sometimes, tach doesnt bounce but I can feel the car kinda shiver if thats the right word. I gave them 6 new spark plugs to put in when they replaced the valve covers hoping that would take care of it. That didnt seem to help at all. I am going to check though and make sure the new plugs are in...If I can tell by looking at them.

 

Idle should be 700 rpms +/- 50 rpms according to FSM. You'd notice if it was low because it starts to putter.

 

its definitely closer to 600. I do have a plenum spacer on there and have cleaned the throttle body (that resulted in a 1200 rpm idle) it was nasty as hell. After the ecu, throttle position, and air idle procedures it came back down to 600ish, but I guess 650 is 700 -50 so I am thinking it is in spec. I will try another idle air learn.

I wouldnt call what it does a putter, more of a little shake every couple seconds while sitting idle.

 

you're fine if it seems normal. lower than normal idle and you will know. Feels like the engine is struggling to stay alive.

 

so after checking the idle on the way home from work, and redoing the idle reset procedure, it is definately idling close to 600. I would guess 625, but is the tach that accurate? I wouldnt think so.

oh and no parts stores around here have the pcv valve in stock.

 

"they all do that"

stock tach isnt perfect. it will read slightly off

 

the hissing is completely normal... if you previously had cover on, you probably never noticed the sound...

 

only cost me $11.50 or something like that at the Nissan dealership...get one there. They should have one in stock.