I have a 2013Soul exclaim that I purchased used last year. It had 52k on the clock, now 58k. This car was mint inside and out most definitely garage kept and very well maintained with records. I noticed that once in awhile it would run a little bit rough at idle.Given that direct injection has a tendency to carbon up the valves despite continuing fuel treatment/routine maintenance, I decided to try the " Italian Tune up ". The results were a bit frightening. I accelerated to 30mph on a flat stretch of road and then floored it. The car launched like a rocket ! When I peeked in my rear view all I could see was a massive cloud of yellowish, gray smoke like I hit a smokescreen button. Knowing about how the motors like to grenade themselves, I was reluctant to do this but it seems to have worked. The idle isn't rough anymore and seems to be running quite smoothly. I've performed a hard acceleration a few days later with no noticeable smoke coming out of the tailpipe. Maybe it needed this and maybe I got very lucky, damn lucky that the motor didn't explode. Thoughts?