My left analog stick moves down alone? what should I do?

Try this my dude.

Marcelo Marques, that is the sign of a wore out analog controller. You will have to replace it. The controller is available at places like this This will require to unsolder the old one and then resolder the new controller. Hope this helps, good luck.

I had the same problem but I guess i had to trick my way through it...lol! When it shifts to the unwanted position calibrate it and make sure no button is pressed during calibration...this is more like making a new setting over the default. Thank me later... cheers

I had the same problem. I opened up my controller and removes the thumb stick. I opened up the green box on the left of the analog stick on the there was some black residue on the contact. I cleaned it out with rubbing alcohol and it works fine now.