[Dark_Kostas]

Its fully working on me, i tried that one.

pawn Код:

public OnPlayerUpdate(playerid)
{
  if(IsPlayerInAnyVehicle(playerid))
    {
        new currentveh, Float:angle;
        currentveh = GetPlayerVehicleID(playerid);
        GetVehicleZAngle(currentveh, angle);
        new str[32];
        format(str,32,"%f",angle);
        SendClientMessage(playerid,COLOR_ZOMBIE,str);
        if(floatround(angle) == floatround(LastA[playerid])+180 || floatround(angle) == floatround(LastA[playerid])-180)
        {
          SendClientMessage(playerid,COLOR_ZOMBIE," You did 180 !");
            //Kick(playerid);
            return 1;
        }
        LastA[playerid] = angle;
    }
    return 1;
}

The only problem is that, if you are steering left or right, it will not detect you.