Speed and direction with a MC

I am having a problem with this actionscript, i post it on my mc but it doesnt work. (except for the turning it just wont go forward or back)

[color=royalblue]CODE:[/color]
[color=#4169e1][/color]
[color=royalblue]onClipEvent (enterFrame) {
//This code will advance the car forward.
if (Key.isDown(Key.UP)) {
speed += 1;
}
// This will make the car go backwards
if (Key.isDown(Key.DOWN)) {
speed -= 1;
}
//The car will start to slow down after the speed of 25
if (Math.abs(speed)>25) {
speed *= .6;
}
// This will change the angle of the car
if (Key.isDown(Key.LEFT)) {
_rotation -= 10;
}
if (Key.isDown(Key.RIGHT)) {
_rotation += 10;
}
// This will make the car move
speed = .98;
x = Math.sin(_rotation
(Math.PI/180))speed;
y = Math.cos(_rotation
(Math.PI/180))speed-1;
if (!_root.move.hitTest(_x+x, _y+y, true)) {
_x += x;
_y += y;
} else {
speed *= -.6;
}
}

[/color]