What movie was about a guy roaming the wasteland with and guitar?

You're likely thinking of the movie "Mad Max: Fury Road". While the main protagonist, Max Rockatansky, isn't known for playing a guitar in the film, a key character named "The Doof Warrior" plays a massive electric guitar mounted on the front of a war rig during the film's chase sequence.

The Doof Warrior's music is a powerful symbol of defiance and rebellion against the oppressive regime in the film. His guitar playing is memorable and iconic, and he is often considered a highlight of the film.

However, if you're thinking of another film, please provide more details about the plot or the character's appearance, and I'll do my best to identify it.