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.
When I removed this one, I found one of the lead wires broke! 
Simple fix…re-strip the wire, and re-solder! 
While I was at it, I went ahead and did a restring and cleanup 
These brass pegs were interesting 
Strings slot through a hole, and I had to insert them a little differently 
String button with a little slack first, then insert brass peg 
These things not only add resonance, but give the strings a slightly brighter tone than they normally would! 
Restrung and cleaned up!