Algodoo

REALLY unstable. If someone knows how to solve this problem, just comment, or make a response scene.
Well, a good thing is that you can drive it for a few secs without making it explode .
So, controls:
NUM1 - gear 1
NUM2 - gear 2
NUM3 - gear 3
NUM4 - gear 4
NUM5 - gear 5
NUM6 - gear 6
NUM0 - clutch
NUM. - reverse
DOWN - brake
UP - accelerator
That's all I think.
Please help me fix this!