first off, its snowed the other day and the streets were real icy, i was cruising about 35 mph in 4th gear with my foot off the gas pedal and all of a sudden, i break into this spin and did a couple 360's on a main street, and on dirt roads i can feel my rear end kinda "float" around..what could be the problem? And other problem is when i rev up i can hear this flapping noise, almost like a plastic bag held out a window flapping in the wind, but its not that loud. It comes from under the car, so do you think its an exhaust leak? thanks

 

did you hit anything?

 

did you touch the brakes all? Stangs gotta fat *** and swing pretty easily in slick conditions.

 

Okay, you had to hit something.

My guess is that the 'flapping' noise is an exhaust leak.

The floating could be a number of things. (What do you mean? Floating up/down, front/back, left/right - crusing, accelerating, braking???) Check your control arms and the mounting points. Check your rear sway bar and mounts. Shocks and mounts. Etc.... In other words, put it in the air and inspect the rear of your pony.

 

If you spun out you probably hit something, possibly bending an axle flange, jack your car up and check your wheels for lateral runout as well.
John