Neat Audi S3 cleaned. In this picture on the right you can see the restriction the carbon creates when the valve is open. Considering this car has less than usual build up its still closes a good portion of the port. The injectors where marked as the customer requested us to change one out for him. This is a free service and can save customers paying twice for labour. So if you need to change injectors its a cheaper route to get a Carbon Clean and have them swopped for free.