I had this start with my phone around December 2012. It only affected Bluetooth, so I didn't worry too much as I don't use Bluetooth. Then my Wi-Fi started copping out about a month ago. I did some research, and it looks like it's hardware related.
I have an extended warranty that I've paid into every month since I bought it (December 2011). I called the warranty company up, and because it was out of manufacturer's warranty, I had to drop $150 on a new phone. I also spent close to an hour trying to explain to them that I had done nothing wrong to the phone. Apparently, it is in the same category as it being stolen or broken. I was so choked. I've babied this phone like crazy, in fact, it still has the protective cover you find on it when you open it fresh out of the box (I just cut off the tab). I was livid.
Well, my amazing wife ended up calling Samsung directly. The call lasted 5 minutes and they didn't even question the integrity of the phone (other than what I did to fix it and the problem itself). The representative said that because we had never called them before, they would replace it for us, free of charge. I question that they might know there is a defect that happens as this isn't a one-off, but I'm very satisfied with their service. I'll be
If you can produce your original receipt, call Samsung. They should do the same thing for you as they're doing for me. Ironically enough, I'm reverting everything back to stock and backing everything up and happened to see your post.
Hope this helps and good luck.