In , there is no official "auto-strum" setting or cheat code in the base game. To play without manual strumming, you must use specific controller modes or mods . 1. Gamepad Mode (Official Workaround)
These tools allow you to map your guitar's fret buttons to trigger two actions at once. The Setup: guitar hero 3 auto strum pc
For a visual walkthrough on setting up keyboard auto-strumming: In , there is no official "auto-strum" setting