PO 0303 CEL Code and Coil Packs
 

After July the 4th weekend when I started my car the check engine light came on and it sounded like it was not running on all cylinders. When I plugged it In I got PO 0303 and PO 0300. I believe 0303 is a misfire on cylinder 3 and 0300 was triggered by 0303. After doing a little research and talking to my mechanic I believe the cylinder 3 coil pack needs to be replaced. I got to this conclusion because I was told they sometimes act up as a result of moisture and my car was sitting either outside or in my muggy garage not running for almost a week without being started which is not typical for it. It has been less than 20K miles since I had the last major service done which involved changing the plugs (but not the coil pack)

At this time it's been three weeks since I cleared the code and it has been running perfectly. My questions are

1. Should I be concerned that sometime in the near future I will have the same issue and should i go ahead and replace the coil pack?

2. Should I just replace all 6?

Thank you