Azizi,

    "Where"; Central Missouri.
    "When"; This would have been around the early to mid seventies that I actually became aware of the usage.
    "Who"; Rural, Caucasian teens.
    "Why"; If one were to drive a car/vehicle hard like teens are wont to do you can expect severe wear and tear on your vehicle and if you drove fast enough over a whoopty do your car got airborn then crashed back down on tires and suspension often bottoming out. This always led to turning cars into junk the steps being;
1) my new??? (to me) car. That you tried to take care of.
2) The car, Was just transportation.
3) Whoopty/hoopty, a car that you didn't take care of. Too many trips over the whoopty dos, or too many Brodies (donuts), or too many trips into a farm field at 70 mph.
4) Fishing/Farm car, only good to drive around the farm or to your favorite fishing/swimming/party place. Usually meant that you had just gotten another "NEW" to you car.
5) Field car, when your car finally succumbs to the punishment that you've so skillfully dished out and has to be parked in a field somewhere because it will no longer run.

Hope this helps. It kinda surprises me that no one else has a similiar tale. Surely we werent on the cutting edge...LOL

Pax.
Chip2447