awesome22

I had my pistons replaced in Sept (took them about a week since they also had to order the parts) under the CSP for my 2009 IS250 @ 47K miles. All was well until last month when I started to feel the car idling strangely when at a stop. It happens every so often. No engine light. I mainly use mid-grade gasoline from Shell (newer stations). I've put on about 7K miles since Sept. Could my car be getting carbon buildup already after 6 months? Should I try a fuel additive like SeaFoam?