Bro my car does the same exact thing all the time, I was watching it do it last night, pretty much when I hit a stop sign or red light she drops anywhere between 650 n 530 so I'm thinking it could be a coil pack not sure. This still happens even after cleaning my throttle bodys n MAF but just not as much.

 

If you ask me, it’s your idle causing it. Get those TB’s cleaned, MAF’s and do the relearns and you should be perfect.

Funny enough, mine runs rough at 650... Mine bounces around a bit, which is puzzling because I did all the relearns and cleanings, but I might do them again soon. I haven’t done anything as far as digging into the vibration, I haven’t because the wallet is empty for school, but I’m quite sure it’s a motor mount or tranny mount.

 

Yea I did all of the above more than once, cleaned throttles MAF n changed the filter with the relearn procedure.

 

Check your mounts

 

My mechanic is gonna have my car for a whole week while we are on vacation. I've instructed him to go over the entire car and check for any and all issues, which includes this vibration issue. I'm gonna provide him with a list of the possible causes (and solutions) as stated here on the forum.

 

If one mount ends up being bad replace all motor and trans at same time

 

Will do! Thanks!

 

There was another member around here that had an issue with his fuel causing roughness, but also he had lack of power. it doesn’t sound like that’s your case. Even still, hows the gas your using?

 

Update:
I thoroughly cleaned both throttle bodies last night. There was some gunk, but nothing crazy. Put everything back to together and did Idle re-learn etc... NO change in RPM and vibration is still there when RPM's are at 500. Idle was never rough, just sometimes it drops to 500 when at a stop in drive (D). As I mentioned, sometimes when I come to a stop, it idles at 650 RPM and I feel NO vibration. However, more often than not, it idles at 500 when at a stop. Basically, it seems to be an intermittent issue. I can be driving around town and stop at one light and I'm at 500 RPM. Then, I come to the next light and I'm idling at 650 RPM. And, there is no change in A/C, stereo, or any other loads. Hopefully, my mechanic can figure it out. If the issue was, let's say the engine mount(s), wouldn't the vibration issue be consistent every time? Also, bad engine mounts wouldn't cause the idle to be 500 one minute, then 650 the next would it? What about the IAC? Does the G37 have an IAC valve? If not, what other part(s) are on this car that control Idle speed? I guess if my mechanic can't find the problem, I may have to take it to the dealer.

 

Damn was really hoping cleaning the throttle bodys would do the trick for ya. Im really interested in finding out what's causing your weird idle because my G is experiencing the same issue as of now. Keep us posted if you get it solved or not.

 

Do you hear belt squealing? Your belt and tensioner could be wearing out causing this

 

I've been through the exact symptoms you've described. The vibration noise is likely independent from the idle behavior.
Can't help with the noise if you've already checked the washer fluid reservoir clip...
However, I did the TB cleaning, and idle relearn... no dice. It took a funny reset sequence, full ecu reset (pedal dance or neg. battery) - TB position reset - idle relearn.
Found all the procedures somewhere in the DIY section.

Is the car new to you? Have the computers been reset recently?I IMO its not a mechanical issue. May be that the car has learned in a different environment.

 

Nope, no other issues (that I can detect).

There is one tidbit of additional info to add: There was an instance or two when the idle would go to 650 RPM after coming to a stop. It was a long stop, so I was watching the tach to see if it held. It stayed at 650 RPM for about 30-45 seconds, then dropped to 500 RPM and stayed there. A/C was on at the time. I get the same issue regardless of whether A/C is on or off. There has to be something that controls idle that goes goofy at some point, that causes the idle to drop to 500. So far, it has NEVER dropped below 500 RPM and/or to the point of feeling like it was gonna stall. And, to reiterate, the idle (at any RPM) is always smooth.

 

Yes, I got the car about a month ago. I didn't get it an Infiniti dealers, but was a 1-owner in very nice shape. Carfax was clean and it had regular maintenance done at both Infiniti and Nissan dealers. I bought it with 61k miles. I took notice to the vibration something immediately, but didn't think anything of it and figured it was just a trait of this car. As time went on, and in browsing through these forum pages, I discovered that this seems like a somewhat common issue. What's the reservoir chip noise you are talking about? What noise does it make? So the funny sequence reset procedure resolved your issue? As for the computers... yes, they have been reset several times over the last two weeks or so. If you look at the previous posts here, you'll see the Pivot Mega Raizin voltage regulator that came with this car. I took it off to see if I noticed any difference. in doing this, I disconnected the battery. I also re-installed the Mega Raizin to see if there was any difference--not sure I notice anything. I might remove it one last time and be done with it. Anyway, with each install/removal, I disconnect the battery. I've done an idle relearn after each time.

 

Sounds like pulley is on it's way out only thing I can make sense of since its sporadic right now