I have to ask... not trying to be a jerk... you are printing to the printable side of the media right and it is ink jet printable media? The discs are closed when you insert them into the player??? What kind of car deck are you having issues with?
I don't own an Epson printer, but I have received some cd mixes from friends that have ink jet media and they play fine in my Pioneer car deck.
The players in question are my brother & my brother-in-law's. The former player won't except any discs I've printed (correctly ;-) they work in my car), and the latter, has so far, only failed once. All using the same blank media.
The players are stock to the Tahoe & Toyota truck, respectively.