whats wrong with my controller?

[aegisjester]

I'm not super savvy with DDR controllers (I've only been playing for a couple of months), and the ones I'm using came with the game (DDR Universe 3 for xbox 360)

my problem is that while my skill has been going up (I can finish just about every expert song now), my scores have been going down because my controllers have been acting wonky. Mostly, it is either recording way too many steps, or ignoring it when I do step (almost all on the left button, but sometimes on the top).

They don't have this problem when I first use them, but after 2 or 3 songs it gets almost unplayable (and completely unplayable if I want a record). I play on carpet, with regular cotton socks.

Is there something (simple) I can do to fix this, or are they just shot?