I have a 2004 Z and lately noticed a sort of humming from the cabin with a slight higher pitch. Is there any way to tell if something wrong with the pumps? Thanks in advance.

 

Bump (problem similar to mine.)

 

Like many parts, you just don't know when they are going to fail, and sadly, a fuel pump usually doesn't fail gradually. It works or it doesn't. If you do a search, you'll find a lot of ideas which might buy you some miles if you have a complete failure. All the way from hitting the tank with a rubber mallet, checking the fuse in the box under the hood, and other things.
But, I can say this. I've had several other GM products, trucks, Tahoe, Yukon, etc. and they all have had fuel pump issues. I believe the vette is similar in concept to those vehicles. The fuel is used to cool the pump. As such, it is highly recommended, to get max life from your fuel pump, to not let the tank get low. Keep at least 1/4 tank or more in the tank. Also, change the filter. Low fuel allows more junk to clog the filter. A clogged filter makes the pump work harder, and fail sooner. Of course, since the filter is in the tank on the vette, it's not an easy change, which is yet another reason to try and keep your fuel level up.

My first experience with the fuel pump issue was on the wife's yukon. She always ran the gas down to the fuel light and plus some. She burned up a fuel pump around 35,000-40,000 miles. That's when all this was explained to me. It was actually explained to me by a non-GM guy who did most of my work, and reiterated by the dealership guy.
And I can say, when those pumps are going bad, they scream. They just get louder and louder, then they fail. I remember that yukon just howling.
So, if you have a pump that's making lots of noise, my history suggests it is on the downhill side of its life.
Of course, remember, you've got two tanks in the vette. Also lots of posts about how those tanks work together.

 

Oh, you might check your rear dif, make sure good fluid, topped off, etc. I don't think you indicated the sound was at idle, which would suggest to me it's a fuel pump. If driving, could still be the pump, but might be diff. I think that's less likely.

 

Yeah the sound is at idle as well. Good info so far.

 

Any fuel pump sounds come from behind the driver's seat. Trying turning on the blinker while you are idling and listening to the sound. If its varying at the same time as the blinker and its coming from behind the seat, then its your fuel pump. But, having said that, it will probably keep right on running just fine. As they get older, they get a little noiser. When I gave away my '99 to my son in May, it still had the original fuel pump and the car had 310,000 miles at that time. He drove it from here in S. Calif. all the way to Virginia without any problem and I hear its now up too 316,000 and still running perfectly.

 

By coincidence, today my fuel pump made a higher than normal pitch whine when I turned the ignition on, but before starting the car. It has been really hot here, so it may have somthing to do with the level of the tank and the temperature. (half a tank, and 103 deg.)
I drove it later, and the noise went away. Also, I could not hear it when the car was running, just when the pump cycles with the ignition on.
I guess if it is not constant, there is no reason to worry.