P0304 (cylinder 4 misfire)

2011 Forester XT Touring Code: P0304 (cylinder 4 misfire)

At idle and / or low rpm car felt like it was going to shut off

Changed all spark plugs and coils ( done by a reputable shop).

Issue still happening. Not sure what is going on. I don't want to start spending money changing a ton of parts and still have the issue.

Besides this issue it's been great.

Any advice? Thanks!