I have a bad whining noise coming from my car. it never does it the very 1st time i start the car for that day, but after i have driven it somewhere and let it sit even for like 5 or 10 mins..75% of the time it'll make the noise. it sounds like it's coming from my exhaust pipes and more so on the passenger side. it will go away after i start driving the car but it usually won't go away if i just have the car sitting idle. A local shop told me possibly fuel pump...but why am i hearing it out of my exhaust pipes and louder on the side that's not where the fuel pump is? what could it be?

 

It's probably your AIR pump, that thing that warms up your cats for a few minutes before the car gets up to operating temp. My car used to make that "whistling" noise, almost like a small supercharger, before I took all that bullshit EGR and AIR piping off and disabled the AIR pump.

 

i would tell you what it is but he nailed it ^^^^

 

The air pump is located in the drivers side fender. Take it off its its not required for emissions in your area, You'd be surprised how much that pump weighs.

If you know someone who can plug in HP tuners or EFI Live in, get them to switch the air pump on and off to see if it is that creating the noise. I'm pretty sure it is though.

 

Remove the supercharger.