rumbling noise during idle on G35

[PGrated]

For the last week, I have been finding that there is a low rumbling noise coming from somewhere on the car. It only occurs after the car has been warmed up completely and I am not moving. It is slightly more noticeable when the car is in "drive", but is still there when in neutral or in park mode. When I am in park and I hear it, it goes away when I press the accelerator a bit. I can only hear it while I am sitting inside the car with the doors closed. I can't hear it when I am standing outside the car. I can hear it slighty, when the hood is up, close to the firewall. It is most prominent on the passenger side of the car, and it seems to be coming from right behind the dashboard, near the center console. I it is not the ventilation system, since I have that completely off and it is still there.

It has a rumble very similar to an exhaust noise, almost like a leaky manifold. The car, a G35X, has 26500 miles on it. Aside from the oil changes, the last one done about 1500 miles ago, and the 15000 mile invterval service, I had a 4 wheel alignment done after getting new tires at about 23000 miles.

I have the car scheduled in tomorrow to check it out. I just wanted to know if anyone else has an idea what it might be beforehand.

Thanks in advance!!pgrated

[AZhitman]

I have a very similar symptom on my Coupe - I've been told twice that "it's normal".

Keep us posted, let us know what you find out!

[PGrated]

Here's an update on the noise I heard...

First, let me also describe it a bit further: The noise was very noticeable at low RPM's, but also increased in speed as I pressed the accelerator. It almost sounded like a flap hitting another piece of metal...and increased in frequency with higher RPM's.

Anyway, I brought it to the dealer this morning. The technician heard it and said that it is a broken spring in the fuel regulator. I am supposed to pick up the car this afternoon. I will post a note about the final outcome.

pgrated.

[AZhitman]

Good info.

Wonder if it would affect driveability?

Interesting...

[PGrated]

I picked up the car yesterday. They replaced the spring on the regualtor and all seems to be okay at this time. The sound is completely gone. Fortunately, for me it was done under warranty so it didn't cost me anything.

I had the same thought on how it would effect driveability of the car. I'm wondering if it may have something to do with fuel consumtion too. My gas milege for the last few weeks has been abysmal (about 18). It will be interesting to see if this will have any effect on it.

pg

[Q451990]

I've been disappointed with the mileage on our G as well, but I'm waiting for a few more weeks of checking MPG before I get too upset.

The only other thing that I noticed is that this car seems to be geared awefully low... I run 3000 - 3200 RPM at 80MPH in D (or 5th with the manumatic). Seems awefully high to me... certainly a lot of shifting going on with this 5sp. A/T.

Heath