When your going pretty fast, say 60 for example, and your in 6th gear. Does it make a weird sound when your pressing very lightly on the gas (just maintaining speed for example) and go away as soon as you take your foot off the gas, or press harder on the gas? Meaning, the sound is always there while maintaining speed........ Anyone else with this problem? Thanks

 

Can you describe said weird sound?

 

hmmm..... i guess its some kind of humming, or whining sound. It can only be heard with the windows up, and music off ofcourse. Its not sooooo loud obviously, but its noticable. Very, if you listen for it.

 

It's the sound of your Z whispering to you "c'mon man, let's go faster...give me some juice".

 

That was funny has hell!!

 

its the gas pump.

 

If it is coming from the rear it is the gas pump. I am assuming the 350z pumps are in the back of course.

 

The tank is right behind the driver/passenger seat below the storage spaces. I suspect the whine you here is the rear end (diff). I have the same thing and it is a cronic problem (if you can call it that) for the 350Z. It is not that loud and it is normal. My other rear wheel drive cars had similar noises.

 

You're only hearing it is because your engine is barely turning if you're doing 60 in 6th gear! Remember too that the Z is a sportscar and not a limo -- every car makes is own unique music, but in most cars you can't hear the music because of all the soundproofing. As an aside, I can't say that I've ever been at 60 in 6th; routinely cruising, more like 4th to keep some somewhat responsive rpms. I'd consider the Z to really be a 5-speed with an overdrive (6th).

 

I have a slight whining noise at 80 in 6th (3000 RPM). I highly doubt its the fuel pump, since it only happens in 6th (not 5th at 80 or at 3000 RPM). I've noticed it for about 8000 miles now (Z has 15,000 total), and it hasn't really gotten any worse. Don't really notice it any more.

-D'oh!

 

60 in 4th gear? Why would you be in 4th gear at 60?? If your on the highway, wouldnt you want good gas mileage? Im in 6th at 40 if im cruisin for a while. 4th is cool for nice acceleration, but why would you need that all of the time......

 

I was doing about 120 in 6th then i hear this whining noise from the rear so i look around then i see these strange red lights in the back window too, so i push the gas down harder for a while and sure enough it went away. Go figure!

 

Strange. When you let up on the gas, do the red lights reappear?

WayneTN

 

When I first got my Z, I used to go 60 in 4th (first time driving a stick shift). In the last couple of months, I started going all the way up to sixth, and I've noticed that my gas mileage has increased from 18.1 to 19.2, and it still seems to be increasing. The change to Mobile 1 oil may have helped, too. I think I know what whining noise your talking about, I hear it when I'm going at low RPMs.

 

I agree - sounds exactly like diff gear whine to me.

 

I have the same problem and it bugs the crap out of me!
Here is a link to more people with the same issue.
https://my350z.com/forum/showthread....threadid=28544

 

Now 40 in 6th gear is freakin' idle rpm -- have fun carboning up your engine, 'cause it will never be able to go fast after a few thousand miles of that. A few points: 1) This is a sportscar darling, I bought it for performance, not gas mileage, 2) Maintaining good acceleration rpms will keep you out of trouble -- ya can't accelerate out of a tight spot when some fool in a minivan tries to clean your clock if you're doing 40 in 6th -- you're a sitting duck, and 3) 4th gear at 60 is cruising -- 3rd gear at 60 is ideal for top acceleration.

 

I have the same whine around 80-90mph

 

you guys ring the hell out of your engines. I cruise in 35 mph areas in 5th, only when the speed limit is above 45 do put it in 6th.

TereP: I seriously doubt that this is damaging in any way, you have all of this low end toque why not use it. Now i wouldnt begin to use 6th at 40 that is a little extreme.

 

Try hitting it to the floor doing 35 in 5th and feel the engine bog deeply. That is a carbon building exercise. You don't get decent torque until you get above 4,500 rpm. What you might interpret as torque in the lower gears isn't -- it's the gear ratio -- first has a very high ratio for an unmodded street vehicle. The Z's first gear is almost into a stock drag class gearing. 35mph is nearer to the beginning of the 2nd gear range. You could run 35 in 3rd comfortably, but it's not nearly as responsive. 6th gear is really an overdrive because it's less than 1:1 ratio. It's not wringing the hell out of the engine, it's simply driving the Z the way it was designed to be driven -- like a sportscar, not the family minivan. I don't drive the Z to get simply from point A to point B -- I drive it for the fun you can have between points A and B.