Why does my iPod Classic cut off the end of certain songs?

I have an iPod Classic from 2007 (Generation 5.5, 80GB hard drive).

Something that I've been noticing happening more and more is that some songs will play just fine but then at some point they'll just stop. The little time counter will jump to where it appears there is two seconds left in the song. And it will just sit there for several seconds and then then proceed to the next song.

And what I've noticed is that it tends to happen consistently with the songs that are problematic.

I've searched all over to figure out what might be causing this but I haven't had much lock, possibly because the symptoms are so vague ("some songs cut off", etc.)

My music collection, which is always pretty much filling the device, is 100% MP3 from a wide variety of sources (ripped, bought from Napster, etc.) and everything plays fine in Winamp on my PC so it doesn't seem as if the files themselves are completely corrupted.

My guess is that there is something about the files that the iPod is choking on but I can't figure out what that might be. If I'm lucky it's some weird tagging quirk (i.e., can be fixed in the individual files) but I really just don't know, and it seems to be happening on an increasing number of files, including files that played just fine before. Sometimes an entire album or artist will consist of files that cut off.

If this is just some known issue, do the latest iPod Classics (Generation 6, 160GB hard drives) still have this issue? I'm almost hoping that this is a sign of a dying iPod so I can upgrade :)

The first thing to check is to see if iTunes has marked those specific songs to end early. Next, try re-encoding the song at a lower or different bitrate and syncing it to the device. Often a glitch in the file can cause iPods to skip to the next song, but the same binary file plays through on macs with better code for handling errors. Lastly, it could be error creeping into the filesystem structure on the iPod. Once you're sure you've backed up everything from the iPod, you can enter disk mode and use Disk Utility (on the mac - on Windows there are lots of disk formatting tools) to zero the drive. That will test the actual hard drive for errors and spare out any bad blocks.

Feel free to edit this or comment if you find none of these helps narrow down the cause.