[Fedee!]

[pawn]

pawn Code:

if(strcmp(cmd, "/respawnallcars", true) == 0 || strcmp(cmd, "/rac", true) == 0)
    {
      if(IsPlayerConnected(playerid))
      {
        if(PlayerInfo[playerid][pAdmin] < 3)
            {
              SendClientMessage(playerid, COLOR_GRAD1, "  you are not authorized to use that command!");
              return 1;
            }
            else
            new bool:unwanted[CAR_AMOUNT];
            for(new player=0; player<MAX_PLAYERS; player++)
        {
        if(IsPlayerInAnyVehicle(player)) { unwanted[GetPlayerVehicleID(player)]=true; }
        }
            for(new car = 1; car <= 268; car++)
            {
                if(!unwanted[car]) SetVehicleToRespawn(car);
            }
            GetPlayerName(playerid, sendername, sizeof(sendername));
            format(string, sizeof(string), "SERVER: All unused cars respawned by %s.", sendername);
            BroadCast(COLOR_WHITE,string);
        }
        return 1;
    }

Try that