Ipod Nano 6th Generation wont play / skips songs

Ipod Nano 6th generation. Songs play fine on iTunes, but skip before playing on ipod nano. These songs are from a range of sources including ripping from a CD, downloading from the store, and converting the audio from videos. This is an issue with a handful of songs, most play fine, and the songs affected previously played fine on my Nano. I have already tried system check and restore on the PC. Please help