2004 S60 non-turbo. The car has been idling rough when cold but smooths out as it warms up. When it idles rough, the check engine light will come on and it's throwing the P0300 code-random misfiring. I'm suspecting a EGR valve stuck open, but wouldn't it throw a code for the EGR then?

This has also happened twice since this problem has started, but it takes a long time of cranking before the car will fire. Not sure if it's related but normally it starts perfectly but has a rough idle first thing in the morning. What could the problem be?

 

Any vacuum leaks? That would not cause a misfire but it could cause a hard cold start. Check real good around any cold start/idle componets.