Combustion Chamber

WARNING: This page is about a different car, the 2010 Suzuki Kizashi. However, it is still accessible from the selected car via links, so may be relevant.

Remove all carbon deposits from each combustion chamber.
NOTE: Do not use any sharp-edged tools to scrape off carbon deposits. Be careful not to scuff or nick metal surfaces when removing carbon deposits. The same applies to valves and valve seats, too.
Check cylinder head for cracks on intake and exhaust ports, combustion chambers, and head surface.