Does your sound go in and out when you jiggle your cable when your acoustic/electric is plugged into an amp? First verify that it’s not the jack itself by using another cable. If the problem persists on another cable, inspect the jack itself. The main problem with acoustic/electric jacks is that it replaces the strap button. This added pressure can often cause problems with the jack itself. To verify the jack itself is bad, you need to remove it.