public OnPlayerEnterVehicle(playerid, vehicleid, ispassenger)
{
    new mot, lu, alar, por, cap, porma, ob;
    {
        GetVehicleParamsEx(vehicleid, mot, lu, alar, por, cap, porma, ob);
        SetVehicleParamsEx(vehicleid, mot, lu, alar, por, cap, porma, ob);
    }
    return 1;
}

public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
    if((newkeys == 4) && (IsPlayerInAnyVehicle(playerid)))
    {
        OnPlayerCommandText(playerid, "/motor");
        return 1;
    }
    return 1;
}

public OnPlayerCommandText(playerid, cmdtext[])
{
if (strcmp("/motor", cmdtext, true, 10) == 0)
{
    new mot, lu, alar, por, cap, porma, ob;
    new carro = GetPlayerVehicleID(playerid);
    if(carro != INVALID_VEHICLE_ID)
    {
        if(motor[playerid] == 0)
        {
            GetVehicleParamsEx(carro, mot, lu, alar, por, cap, porma, ob);
            SetVehicleParamsEx(carro, VEHICLE_PARAMS_ON, lu, alar, por, cap, porma, ob);
            motor[playerid] = 1;
           }
        else if(motor[playerid] == 1)
          {
            GetVehicleParamsEx(carro, mot, lu, alar, por, cap, porma, ob);
            SetVehicleParamsEx(carro, VEHICLE_PARAMS_OFF, lu, alar, por, cap, porma, ob);
            motor[playerid] = 0;
        }
    }
}