Problem with SYNC and iPod

Anyone having issues with SYNC no longer communicating with an iPod?   My iPod worked great from day one in February of this year.  Last week I told SYNC to play a certain play list and the “nice lady” said, “Speech control not available with this device.”  She gave me the same message with every command except pause. Speech commands worked at 7:30 that morning but not at 4 PM that afternoon.  Nothing had changed. I hadn’t disconnected the iPod.  And interestingly, on Friday, three days later, it started to work again.  Now each time I try it, I wonder if it will work.