The Audi S5 V8 is known for its smooth power delivery, great sound and strong performance. But like many direct-injection engines, it can develop a problem that isn't always visible from the outside — carbon buildup inside the intake system. This S5 came into Revhigh for a walnut blast and carbon clean to remove accumulated carbon deposits and help restore proper airflow through the intake system. So, Where Does All That Carbon Come From? As the engine operates, carbon deposi