Loud sound coming from back of tiburon, gets louder at higher speeds

Noises are decieving. Cud be steering system or wheels or suspension. If ball joint fails car cud flip ovr.hav pro testdrive it. Seek a gudguy at surecritic.com

Check the flaps, could be sticking, or broken

means your transmission is slipping . that would be your over drive and 3rd and 4 th shift solenoid

I've just bought a K13 Nissan Micra and it doesn't sound quite right. The noise I hear also seems to be coming from the back but it sounds like when you chop down a gear in a manual going down a hill and the engine revvs, well this is the noise I get in the automatic speeding up and slowing down, even just cruising at a steady speed. Any ideas people? Apart from this noise I love this car.

jack car up in back and rotate wheel by hand to see if one of the two have a grinding noise or doe s not rotate freely.. that would be the one with bad bearing.

sounds like the wheels are out of balance, is there a slight vibration through the steering wheel at this speed? and does the problem stop if you go faster (please drive carefully)

I would suspect it is a wheel bearing issue, if it sounds similar to a baseball card in the spokes of a bicycle, stays somewhat same pitch just louder with speed that is where I would look. Does noise go away or change when making turns?

Front Wheel Bearing Hub

You will have to remove the brake calipers,hang it,&
remove the rotor,then you can turn the hub & feel the
roughness.

ROCK AUTO.com for parts & look at that hub, so you
match it up the same. Don't get in love with one brand
you like, if the hub looks different at the back where the
speed sensor goes in

You also may find your self buying a torx socket or metric
socket driver to get the speed sensor out. Maybe not

If tools are needed,do yourself a favor & step inside a Snap-On
Truck & just buy one item or so. If you don't ,you won't find those
items anywhere

It is definitely one of your idler pulleys is bad or the water pump bearing is shot. They will all make a rattling sound when worn. Either one of those goes and you're stranded. Have it looked at asap.

What kind of noise? Humming? Screeching? Can you tell if it's coming from front? Left? Right? Does it get louder the faster it goes? Higher pitch?