so im hearing a TINY whine/squeal. it sounds like a whistle but i only hear it with windows down music off and over 55. i am guessing its my CAI because it makes a bit of a whistle when i rev my engine but not like this. any ideas?

 

could be something, like a stick or twig stuck against your driveshaft, maybe. it could have gotten jammed under your undercarriage. < that sounds more wrong than it really is but maybe check that out.
my silverado had something fall between the cab and the bed and get stuck rubbing on the driveshaft, made some noise and sounded odd.

 

Could be from the tires; uneven wear is very common and makes a sort of similar noise to what you describing.

 

If it's whine then it's likely the differential.

 

High pitched hiss? Almost a cross between a whistle and a hiss... Definitely CAI.

 

It's probably coming from the back. The diff will start to whine after a while in the car. You can try to change the fluid. If it's what I'm thinking....It's not loud, but just enough to be annoying. If you lay off the pedal it stops right?

 

@syner that is what i am thinking too but i will have a look at the dif and no even if i lay off the pedal it keeps going til the speed drops. ill be looking under the car but what exactly am i looking for? and one more thing sorry guys but bad luck comes in pairs. today i went on a very bumpy dirt road and heard something scrape and now occasionally it makes a metal dragging sound. i have a feeling its the flex pipe.

 

I can't remember if you mentioned this. Does it make the whistle in neutral as well? Or only under speed?

 

im not sure i haven't tried but it does make the noise even if i let go of the pedal until the speed goes under around 50

 

That cancels CAI then.

The Z's differential does start to make faint whine when put some mileage on it. It's normal.

 

well i got about 110k so that makes sense haha thanks! do you have any idea what the metal dragging noise is? like i said it was a bumpy dirt road and i scraped something under the car. i have a feeling its the flex pipe stretching but if anyone else could chime in that would be great