Hey guys and gals,
The last 2 times I've done a cold start on my G coupe, when the engine kicks over and revs, there is a quick 1 second loud vibration noise. It sounds like a thin sheet of metal vibrating against something else. Possibly exhaust or cat heatshield?

Anyways, I am going to try to jack my car up and cold start to try to find the source, but has anyone else had this problem and where was it? How'd you fix it? I'm hoping it's something simple like a loose bolt. Thanks!

 

is your A/C on?

 

No, my A/C is not on.

 

i get that too... no idea why.

 

That's strange. Do you have any mods or have you taken anything apart recently? It's under warranty best thing to do is use the warranty and let the dealer find it. Keep us posted and let us know what it is.

 

I had the same problem at 1800-2000 RPM and it would sometimes do the same on a cold start.

It was the heat shield rattling - requiring the loose washers be replaced and then tightened. It is now not doing it quite as badly, but maybe because I'm used to hearing it that I noticed 'any' kind of different sound at 1800-2k. I haven't heard it at startup since, though.

If you bring it in, make sure you give it time to cool down. I'm sure the Infiniti Tech is going to crank it up and it won't make that sound when it's still warmed up (that's what happened to me the first time - frustrating when I drove in at 7.30 AM in high traffice 10 miles out of my way).

Good luck!

 

Thanks! Your post confirmed my suspicion. I want to try to fix it myself because I don't think the dealer will be able to replicate the problem (cold start). The problem is I have to roll it up on ramps and I'm not sure if I have the clearance to do that!

 

I've got that same noise as well at start up & various RPM's. It started after I got my Ypipe installed. At 1st I thought it was the pipe but I guess I'll have the dealercheck into this as well when I get my exhaust installed.

 

dont forget your timing chain tensioner uses oil pressure. A little quick chatter is common and somewhat expected with a VQ. But it can be any number of things as mentioned above

 

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This is a normal condition with VQ engines. It seems to be the nature of the beast as I've noticed it on a previous Maxima, the G-Sedan, and now on the G-Coupe. It doesn't always do it, but does it more often when colder.
It's something similar to the VDC activating, and the ABS self test that you may have heard on initial startup also.

No worries. Quite normal.

 

i get that noise 2.

 

I guess I'm somewhat relieved My bone stock G did that a few days ago, but only once. It sounded like the anti-drainback valve didn't work in my oil filter, as I know that's what my dad's old car sounded like, when he used fram filters. I thought maybe I had a bad batch of Mobil-1 filters or something....