Hello, i am new to the Rx8 club. I got a rx8 and its got a po300 code. I just changed the cat spark plugs and drove for over 500 miles. The cel wont go away. what can I do, should i erase code?

 

Did you change the coils? That's usually the main cause of misfires. You can clear the code and see if it comes back.

Even if it doesn't come back, make sure you are on fresh coils. Dead coils are a silent killer.

 

are coils expensive and hard to replace?

 

About 3/10on difficulty of replacement. As for expense, a couple of hundred but cheaper than a new engine.

Make sure you read thoroughly the "New and Potential Owners" thread. It has everything you need to know.