[member]

You need SetTimerEx.

pawn Код:

#define MAX_SERVER_PLAYERS 27 //change to ur server max player +1

new AutoVehFixTimer[MAX_SERVER_PLAYERS];

public OnPlayerCommandText(playerid, cmdtext[])
{
    if (strcmp("/carfix on", cmdtext, true, 9) == 0)
    {
        new Float:health;
        new veh;
        veh = GetPlayerVehicleID(playerid);
        GetVehicleHealth(veh, health);
        if(health <500) SetVehicleHealth(veh,1000);
        GameTextForPlayer(playerid,"~w~Auto Car Fix ~g~On!",1000,5);
        AutoVehFixTimer[playerid] = SetTimerEx("autofixtimer", 5000, true, "i", playerid);
        return 1;
    }
    if (strcmp("/vgodoff", cmdtext, true, 8) == 0)
    {
        GameTextForPlayer(playerid,"~w~Auto Car Fix ~r~Off!",1000,5);
        KillTimer(AutoVehFixTimer[playerid]);
        return 1;
    }
    return 0;
}
forward autofixtimer(playerid);
public autofixtimer(playerid)
{
    new Float:health;
    new veh;
    veh = GetPlayerVehicleID(playerid);
    GetVehicleHealth(veh, health);
    if(health <500) SetVehicleHealth(veh,1000);
    return 1;
}

Good Luck