Yep...What I heard is listed in the article!!
Although Direct Injection provides more power and efficiency, a carbon build-up occurs in the intake valves that over time reduces the airflow to the cylinders, and therefore reduces power. Fuel contains various detergents and can keep the intakes clean. When fuel is no longer being sprayed in the intake valves, small amounts of dirt from intake air and blowback carbon from the crankcase ventilation system cakes on the intake walls, even with air filters that prevent most of the dirt from entering the cylinder.[71] This build-up can become severe enough that a piece can break off and has been known to burn holes in catalytic converters.[72] It can also cause sporadic ignition failures.[72] These problems have been known for some time and technologies[citation needed] have been improved to reduce the carbon build-up.
