Does it show resp=0xF8 every time? If so, I would try telling the IDE it's an Uno, or Pro Mini. Sometimes clones have the wrong bootloader on the '328p (since the uno and pro mini use the same microcontroller - they differ only in the details of the board shape and power supply, and which bootloader they use). It's an easy test, at least. (getting the same response every time, just not the expected one, suggests this - but it's not definitive).
The sync error in general is incredibly generic. It essentially means the problem is unlikely to be a driver issue (though a few people claim otherwise) - but almost any other problem that prevents uploads gives this error.