Hi scotty,

I drive a manual 2015 Mazda 3 with the 2.0 skyactiv GDI engine (60,000 miles). I've been hearing a lot about carbon buildup in these newer GDI engines and I was wondering what your take is on treating it. Should I use something like CRC's intake cleaner for the buildup? I've heard dislodging the carbon that way could clog the cat. Would a manual cleaning like walnut shell blasting be more effective? I'm not experiencing any negative effects of carbon buildup. Yet. This question is really about preventative maintenance. I guess if I really want to see if I have any carbon buildup on the intake valves, I should use a borescope. From my understanding, Mazda has designed the intake valves in the skyactiv engines to get very hot and effectively burn the carbon off. Not sure if that is true...