Cargame is lagging!

1

I’m making a cargame. Everything is working great! Except one thing…
In the 2player mode, I have made it so that player1 drives with the arrow keys, and player 2 is driving with W,S,D,A.
Player1 can drive just as good as in the 1player mode, but player2 is stopping everytime another key is pressed. Even if player 1 presses another key, player2 stops.

Player1 code:

 onClipEvent (enterFrame) {
 // making the car go forward
 if (Key.isDown(Key.UP)) {
  speed += 1;
 } else {
  // making the car go backwards
  if (Key.isDown(Key.DOWN)) {
   speed -= 0.5;
  } else {
   speed *= 1
  }
 }
 //The car will start to slow down after the speed of 25
 if (Math.abs(speed)>25) {
  speed *= .6;
 }
 // rotates the car
 if (Key.isDown(Key.LEFT)) {
  _rotation -= speed;
 }
 if (Key.isDown(Key.RIGHT)) {
  _rotation += speed;
 }
 // This will make the car move
 speed *= .8;
 x = Math.sin(_rotation*(Math.PI/180))*speed*+1.3;
 y = Math.cos(_rotation*(Math.PI/180))*speed*-1.3;
 if (!_root.grass.hitTest(_x+x, _y+y, true)) {
  _x += x;
  _y += y;
 } else {
  speed *= -.3;
 }
}

Player2 code:

 onClipEvent(keyDown) {
 //Forward
 if (Key.isDown(87)) {
  speed += 1;
 } else {
 //Backwards
  if (Key.isDown(83)) {
   speed -= 0.5;
  } else {
   speed *= 1
  }
 }
 //The car will start to slow down after the speed of 25
 if (Math.abs(speed)>25) {
  speed *= .6;
 }
 // Rotates the car
 if (Key.isDown(65)) {
  _rotation -= speed;
 }
 if (Key.isDown(68)) {
  _rotation += speed;
 }
 // This will make the car move
 speed *= .8;
 x = Math.sin(_rotation*(Math.PI/180))*speed*+1.3;
 y = Math.cos(_rotation*(Math.PI/180))*speed*-1.3;
 if (!_root.grass.hitTest(_x+x, _y+y, true)) {
  _x += x;
  _y += y;
 } else {
  speed *= -.3;
 }
}

Please help me! Thanks in advance :+)