I got the 10k pots in the mail today and it still does the exact same thing:(
I've also tried connecting 8 pots to every single mux input. I'm still getting weird numbers.
The last thing I tried was grounding all mux inputs except for mux input y5. When I look at the serial monitor, I'm getting interesting results. y1 and y5 are outputting the same exact value even though y1 is grounded!
Would the 100n capacitor trick still work in this case? Also, would reading the analog pin twice or more help? I tried that by repeating analogRead(0) but it didn't seem to work.