Guitar Track not synced with MP3 track


I don’t know if anyone else has had this problem - I’m trying to lay my own guitar track over an MP3 track. When I record my audio/guitar track, it’s like a half of a split second off from the mp3 track. So annoying. Even though while I’m playing/recording, everything seems to be in sync, when I play it back, the two tracks are off by a fraction. I’m using a Boss GT-001 - I’ve tried changing the settings from stereo to mono thinking that maybe it’s picking up one of the stereo channels and not both, but messing with mono and stereo didn’t make any difference. Any other ideas?

See if this tutorial helps:
Pay special attention to the section: “Setting the recording latency