Just posting an update on my maintenance mentioned in the previous post. I got my car back a couple days ago from the repairs which were carried out. The car actually drives as good as when I first got it if I must say so myself. However they didn't mention any method of preventing the carbon build-up from occurring again, all they said was that it has to be cleaned every few years and they're also still learning about the issues. So if anyone has experience with this, please let us know, I'm not too car savvy myself to know about this!