It could be the AC compressor kicking in and out

 

same ****, 6MT, sounds like a tranny clunck but never notied any rpm change.... I will take a 2nd look

 

I heard the same thing from day one with the car. The dealer could not replicate it, but I can everyday. I think its normal, but just magnified due to the higher-flowing than normal exhaust system.

 

Ya, I always put 93 octane in my car, usually Shell, so I wouldn't think it would be due to too low of octane, but I dunno. I'd be interested to find out what is actually causing it though.

-Stephen

 

Same noise here too. Goes away when I put my foot on the clutch. Was told it's 'normal' for our cars.

 

Have you noticed that anything the dealer can not fix always gets the same reponse of "it's normal for your car"?

 

It happens to mine only after it's been running hot for a while, run it around for a while get the clutch and flywheel hot and then swing by the dealer... It'll rattle! It's definately not the engine it's the flywheel. Sounds like a diesel ping doesn't it!? Basically, it's referred to as "gear rattle".

The flywheel in the G is a double mass flywheel. However, after doing a little research I came across this article where the author describes exactly what we all experience (see below)

The issue with gear rattle is that conventional lightweight flywheels retain the car's original solid-hub clutch disk. First, the lightened flywheel has less mass to damp the power pulse variations. Second, there is no mechanism within the solid-hub clutch disk to absorb the power pulse variations. The result is that a conventional lightweight flywheel with solid-hub clutch may create a noticeable amount of rattle. There is simply no cushioning action at all. Note that this gear rattle only occurs at idle, in neutral, with the clutch let out. It is not heard at any other time. Above idle (even just a couple hundred rpm) and the increased frequency of power pulses outpaces the speed at which the components couple/de-couple, therefore no rattle whatsoever.

http://www.uucmotorwerks.com/flywheel/gear_rattle.htm

The above is a bit more explanation than the typical service manager's assurance "it's normal". Hopefully this helps calm some nerves!

 

I think it just idles funny. I initially thought it was the flywheel as well but when I step on the clutch the tranny clunk goes away. However, you still feel the engine shudder at the same intervals as before. After I installed my new exhaust I really hear it now. But it's normal. I was at a small meet with 2 G's and 2 Z's. All the cars were doing it.

whew.... as long as it's not just me... lol

 

Its not the flywheel thing I don't think because I have this same "clunk" noise and my G is an 05 Auto. /shrug

-Stephen

 

I think you guys are confusing the flywheel rattle with the clunk the engine makes whaile idling. Ex. While sitting in idle place your hand on the shifter, keep it there for about 20 -30 seconds and you will feel clunk. Thats what mine does! I have asked arround but so far no one seems to think this is a problem..... though it sounds like missfire/knock... i am confussed!

 

you know my 6mt makes the same kind of clunck, this is not the dual mass flywheel sound either. I've had every infiniti dealer in Chicagoland check it our and they all say its normal. So I figure since there isn't any performance issuses I will just beat it until this tranny dies.

 

I too have this problem, I first noticed it about 6 months after purchase. Went to a dealer in VA, I told them it sounded like a cylinder misfiring, causing this sort of dull "pop" noise and the car shudders once. They said they could not figure out what was wrong. I then went to a NJ dealer, had a technician actually sit in the car while I drove around, and when the misfire happened I would mention it to the tech, and he would just look at me like I was crazy... he was completely unaware of it happening.

That was when I took my shoe off and beat him repeatedly on the head.

No seriously though, I think it is just the car and we can't do anything about it, except to jump ship.

 

same here! after extended driving 20+miles, at idle only, it sounds, and feels like there is a cylinder misfire. and when this happens sometimes, not always but sometimes, it sounds like it misses so bad that it rattles the throw out bearing. much like the noise that the throw out bearing makes when you turn the car off and your foot is off the clutch. which has also been deemed ''normal for our cars''. 04 6mt 42k miles only engine mod is stillen hfab, always run shell 92 vpower. i have concluded that this is not a traditional missfire. as if it were the service engine soon light would be on with the quickness. but it is definatley WEIRD. i think its obvious that its not a prelude to a major breakdown or anything seeing as how almost all of us experience this without any larger issues. but id still like to know the who,what,when,where's and why's of the situation. id take it to the dealer but i already know what they are going to say....

 

has anyone figured out what the clunk is yet???? Not the throw out bearing noise but the "CLUNK"

 

i recently got my 04 g35 with a jct clutch and flywheel.. when im idling the clutch makes a chatter and when i engage the clutch it quits. anyone else have that problem?