I have a problem with my ps3 controller, the l2 trigger doesn't work and every now and then it works, then stops working. I tried cleaning it in the inside with isopropyl and what not. I also tried resetting it and that didn't work.
You could google the documents for Ps3 duel shock controllers then take it apart and fix it, I've done it with my analog before. Or you could buy a new one. you could get a Ps4 controller, I think it works on ps3s with limited functions forwhatever which probably doesn't effect anything you'll play generally.