clip jam 1.13 255 song limit w/USB connector in car

3 possibilities that I can think of at the moment:

1.) Are all the songs/tracks mp3 or .wma format?

2.) Are ID3 tags present and/or correct for the missing songs?

3.) The head unit in your car has an extremely low database recognition. If this, we can’t help with that. Better to check & see if there’s a forum for your car & see if anyone else has the same issues.