I am attempting to control the position of my computer's cursor using a potentiometer hooked up to my arduino nano. The arduino is running the following code:

int potPin = 3;    // select the input pin for the potentiometer
int val = 0;       // variable to store the value coming from the sensor

void setup() {
  Serial.begin(9600);
}

void loop() {
  val = analogRead(potPin);    // read the value from the sensor
  Serial.println(val);
}

When I ran the following python script, it worked properly and the sensor values were printing out in my terminal.

import serial
import pyautogui

ser = serial.Serial("/dev/cu.usbserial-141220", 9600, timeout=0.1)

while True:
    data = ser.readline().decode("UTF-8").strip()
    if data:
        print(data)

However, when I added a small time delay in the while loop, the output would either get stuck on a single value or take multiple seconds to reflect a change to the potentiometer.

import serial
import pyautogui
import time

ser = serial.Serial("/dev/cu.usbserial-141220", 9600, timeout=0.1)

while True:
    data = ser.readline().decode("UTF-8").strip()
    if data:
        print(data)
    time.sleep(0.01)

I'd appreciate any help fixing this issue.