[Abagail]

Code:

public OnPlayerDisconnect(playerid, reason)
{
if(!IsPlayerInAnyVehicle) return 0;
DestroyVehicle(GetPlayerVehicleID(playerid));
return 1;
}
OnPlayerExitVehicle(p...)
{
SetTimerEx("DestroyVehicle", 10000, false, "i", playerid);
SetPVarInt(playerid, "DestroyVehicle", vehicleid)
}
return 1;
}
OnPlayerDeath
{
if(!IsPlayerInAnyVehicle) return 0;
DestroyVehicle(GetPlayerVehicleID(playerid));
}

public DestroyVehicle(playerid)
{
new vehicleid == GetPVarInt(playerid, "DestroyVehicle");
DestroyVehicle(vehicleid);
}

Untested.