In the photo, the yellow sticker area is potted. If it cracks open from age and heat cycling it will be prone to water intrusion but still work when dry.
A good posibility is to cover the area with silicone rubber to help with life issues due to water intrusion..

 

I would like to add my two cents....

I am getting ready to trade/sell my truck, so i had my truck detailed - exterior, interior and engine bay. Now i am blowing P0308, which is the worst cylinder to get too. I thought i was going never going work on this truck again.... ol'well.

Looks like i will have to spend a couple more hours under the hood....