<sigh>Thanks for confirming my worst fear! Mine did stop working about the time of Tango. Perhaps I should just bite the bullet and reset it, but it's almost as painful as reinstalling Windows.
Then again, rumors are that the AT&T exclusive on the Lumia 920 will end in early 2013, which is also when my contract expires. If I can hang on a few more months, and Verizon picks up the L920, I'll be in good shape.
In my case, wireless sync has always been flaky. I bought the phone with NoDo installed, and wireless sync would periodically stop working. I'd disable wireless sync in Zune and re-enable it, and it would work for another few weeks. Occasionally I'd get
an error code when I'd re-enable it. Generally, this same generic, seemingly all-purpose failure code; at least I don't recall there were any others. But a computer restart would fix it. Since restarting the PC has cured it in the past, I've been focusing
on the computer as the likely cause. But unless it's hardware (and what hardware would it be...WiFi?) it's now been exonerated by a fresh Win 8 install and I need to focus on the phone.