ITunes-to-iPhone sync broken

Question

Both my iPhone and my iMac are top-of-the-line, less than three months old, and are running the latest, most updated system software. However, since upgrading to these glistening, state-of-the-art devices, I have been unable to consistently produce acceptable results when attempting to sync music and podcasts from the computer to the phone.
New songs that I have purchased and downloaded through the iTunes Store appear on my computer in the iTunes library and on the iPhone. However, on the iPhone, the new songs show only as available downloads, with the little cloud/arrow icon next to them. When I tap this, the red square-in-a-circle icon appears, meaning the song is going to download all over again, so if I’m not in WiFi range, I’m outta luck. In iTunes > iPhone > On This Phone, the songs appear, but are greyed out.
Furthermore, most of the podcasts that I have downloaded to my computer and synced with the phone are unplayable on the phone, eliciting a “this episode is temporarily unavailable” message.
So far, 3 things “fix” the first problem.
1. Remove all the music, (by unchecking “Sync Music” in iTunes > iPhone > Music and clicking “Apply”), then resync it by re-checking the box and re-applying. The whole library. Every time I want to add even 1 new song. This takes an hour.
2. A full restore — as suggested by Apple — also fixes it, but alas, this “fix,” aside from being extremely time-consuming and labor-intensive, is only temporary. Within a few hours or days the issue recurs.
3. Tick the box labeled “Manually manage music and videos” in iTunes > iPhone> Summary. With this method, I connect the phone and drag my newly downloaded song from the iTunes music library list over to the right-hand side of the window. An “Add To” device list pops up, and I release the song into my phone. The song now appears in iTunes > iPhone > On This Phone, so I click “sync”. Sometimes this works, but at least half the time, the same exact steps produce the message “The iTunes Library file cannot be saved. An unknown error occurred (-54).” Sometimes this error dialog box persists through multiple attempts to dismiss it.
The podcast issue cannot, as far as I can tell, be resolved even by a clunky workaround. If I want to listen to a podcast on my iPhone, I must manually download it directly to the device via WiFi. This isn’t a fix for me, since my daily routine takes place in rural areas where WiFi is not available. Even a manually downloaded podcast reverts, inexplicably, to the “unavailable” state every time I sync the phone again.
It would be much simpler if the podcast app merely worked the way it used to prior to Mavericks and iOS7 and iTunes 11, by which I mean: podcasts that have already been downloaded to iTunes on the computer should simply sync with the selected device when “sync” is clicked. Alas.
Over the past weeks I have read at least fifteen threads on these issues, none of which offer anything like a workable, permanent solution, and all of which contain innumerable instances of plaintive wailing by frustrated customers who merely want what they paid for. It is a pity that these pretty, expensive gadgets cannot perform even a simple sync without eliciting anger and despair.

Answer 1

Hi there,
I would recommend taking a look at the troubleshooting steps found in the article below.
iTunes 10.5 and later: Troubleshooting iTunes Wi-Fi Syncing
http://support.apple.com/kb/TS4062
-Griff W.