new tank; // at the top

public GameModeInit()
{
 tank = CreateVehicle(info in here);
 return 1;
}

public OnPlayerStateChange(playerid, newstate, oldstate)
{
    if(newstate == 2)
    {
        new CarCheck = GetPlayerVehicleID(playerid);
        if(CarCheck == tank )
        {
            if(GetPlayerScore(playerid) < 5000)
            {
                RemovePlayerFromVehicle(playerid);
                SendClientMessage(playerid, -1 ,"You Don't have the keys for this car!");
                return 1;
            }
        }
        return 1;
    }
    return 1;
}