Analog Stick is Twitchy

Hello all, I would like to say thanks to all you veterans that keep this site running cause it has helped me tremendously with FAQ's i've had and various other subjects. Now I have had to make my first post because I could not find anyone with a related problem through the search engine. It would seem that my analog stick when running homebrew apps or umd's wants to act like it's in the down position when the analog stick is centered. I have replaced the analog stick but to no avail it did not fix the problem. I can move the analog stick in other directions but as soon as i let go or let it go towards its center it goes in the down position. I'd appreciate any input I can get from you guys (Being the masters n all).

hm.. when mine does that sometimes all i do is flick it in the opposite direction and it stops. Is there something pushing against it? maybe inside the case?

i think it is common, mine does it sometimes but i only need to move it to stop the problem...

...of topic a bit, the analog stick is not affected by the hold switch, really weird