Misfire on a 2011 Scion xD Code P0303 ???
 

Unable to find the cause of this #3 cylinder misfire. Going to do a wet and dry compression test to see if the problem is internal.
2011 Scion xD starts fine, but runs pretty crappy. I suspect it's valves or a blown head gasket. It's got around 155,000 miles on it and it puzzles me.

If anyone out there knows what it could be besides an internal problem, please let me know.