[Sandra18[NL]]

Try something like:

//Global:

Code:

new RacePositions[3];

//This should be in the part where the race starts;

Code:

RacePositions[0] = -1;
RacePositions[1] = -1;
RacePositions[2] = -1;

Code:

public OnPlayerEnterRaceCheckpoint(playerid)
{
  ...
  case finish:
  {
    if(RacePositions[0] == -1)
    {
      RacePositions[0] = playerid;
      position = 1;
    }
    else if(RacePositions[1] == -1)
    {
      RacePositions[1] = playerid;
      position = 2;
    }
    else if(RacePositions[2] == -1)
    {
      RacePositions[2] = playerid;
      position = 3;
    }   
    //Rest of that callback....
  }
}