[-Sneaky-]

Код:

if(!strcmp(GetName(playerid), dini_Get(string, "Owner"), true))
{
    if(CarInfo[CarID][Engine] == 0)
    {
        //Start engine
        CarInfo[CarID][Engine] = 1;//This should happen if the name of the player = the owner of the car.
        TogglePlayerControllable(playerid, 1);//This should happen if the name of the player = the owner of the car.
    }
}
else
{
    SendClientMessage(playerid, Red, "You have no keys for this car.");//And this should happen if the name of the  player is not the owner.
}

This should work.