[Ballu Miaa]

This is how its done!

pawn Код:

public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
    if (newkeys & KEY_FIRE)
    {
        if(IsPlayerInAnyVehicle(playerid))
        {
            new vehicleid = GetPlayerVehicleID(playerid);
            SetPlayerVelocity(playerid,150.0,0.0,0.0); //Change 150 to your needs!
                        // This is setting vehicle's Velocity to 150 at X direction!
        }
    }
    return 1;
}