diagnostic

I have a 2007 Mazda3 2.0L w/ 71,000 miles and have been experiencing a rough idle. Eventually the check engine light came on. I had a mechanic run a diagnostic test and code P0300 came back (random misfire). Upon further inspection, he recommended I replace these items: Crank position sensor 4...

Hey guys, I've posted about this before. I've had a cylinder misfire issue, but for a while it seemed to go away. Now its back. Its been getting worse. I've pulled all the plugs and coils and I'm confident its not an electrical issue. Haven't tested compression yet... but I wanted to run...