Reading from Serial port with Vive (SteamVR) resulting in huge lag.

I am developing a Forklift simulation in HTC Vive using the latest SteamVR plugin (V 2.3.0). I want to add a custom fabricated steering wheel to the sim, which gives values based on it's rotation. I already had implemented the simulation controls using Vive controllers and keyboard. But the moment since I added the serial connection reading code, the simulation starts lagging bad. 15-20 fps is what I get just by reading from serial port. Here is the code -

 void Awake ()
     {
         InitializeCOMport();
         StartCoroutine(ReadData());
     }
 
 void InitializeCOMport()
     {
          port = new SerialPort(portName, 9600, Parity.None, 8, StopBits.One);
 
         try
         {
             port.Open();
             System.Threading.Thread.Sleep(1000);
             port.Handshake = Handshake.None;
             Debug.Log("Port open");
         }
         catch (Exception ex)
         {
             Debug.Log("Exception " + ex.Message);
         }
 }
 IEnumerator ReadData()
     {
         yield return null;
         do
         {
             yield return new WaitForSeconds(0.15f);
             try
             {
                 datareceived = port.ReadLine().Trim();
                 char[] charsToTrim = { 'd', 'a', 't', ' ', '=' };
                 datareceived = datareceived.Trim(charsToTrim);
                 //Debug.Log("Steering port: " + datareceived);
                 currSteeringValue = int.Parse(datareceived);
                 
             }
             catch(System.Exception ex)
             {
                 Debug.Log("Exception " + ex.Message);
             }
         } while (true);
     }

I had to read the serial port data this way because when I try doing it using the SerialPort.DataReceived event, I get a time-out exception. With the above Coroutine ReadData() I am able to get the COMM port data, but not using the DataRecieved event. Here is the code that reads the buffer using the event-

 port.DataReceived += new SerialDataReceivedEventHandler(Port_DataReceived);
 
  private void Port_DataReceived(object sender, SerialDataReceivedEventArgs e)
         {
             Debug.Log("received");   //This function is fired with
             try
             {
                 datareceived = port.ReadLine().Trim();
                 char[] charsToTrim = { 'd', 'a', 't', ' ', '=' };
                 datareceived = datareceived.Trim(charsToTrim);
                 Debug.Log("Steering port: " + datareceived);
                 currSteeringValue = int.Parse(datareceived);
     
             }
             catch (System.Exception ex)
             {
                 Debug.Log("Exception " + ex.Message);
             }
             Debug.Log("received");
         }

The above Port_DataReceived() results in Time-out exception and the control never reaches to Debug.Log("Steering port: " + datareceived); this point, as it doesn't get logged.

Is this lag because I am using serial ports with vive? Does anyone have any idea how I can solve this?