Problem with serial reading

Question

Guys, I’m trying to read data from a serial port in c#, but along with the data is being returned too "junk", which makes it impossible to convert the string to integer. Is there any way to make me not lose as much data?

    private void SerialCOM_DataReceived(object sender, SerialDataReceivedEventArgs e) //evento datareceived da portaserial atualizado por um timer com intervalo de 3ms
    {
        if (SerialCOM.IsOpen)
        {
            SerialPort sData = (SerialPort)sender;
            { 
                sData.DiscardInBuffer();
                int data;
                if (sData.BytesToRead > 0) RxString += sData.ReadExisting();
                var teste = RxString.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
                data = Convert.ToInt32(teste[contador]);
            }
     }

With this code I have in the "test[]" array several integer values in string format, but when I try to convert these numbers to integer it shows the following message: "The input string was not in an incorrect format.". I tried using Tryparse for conversion but lost a lot of data, which cannot happen in my application. Could anyone help me with this problem?

EDIT:

//supondo que RxString seja
RxString = "1234 456 789 1341 1334";
//então teste[] será
teste[0] = 1234
teste[1] = 456
teste[2] = 789
teste[3] = 1341
teste[4] = 1334

The correct would be this, which would be easy to convert, but sometimes comes empty information or trash in the string "Rxstring", which causes error at the time of conversion.