Q: I have a 2009 VW with gasoline direct inject and a 2.0-liter turbo engine. It recently needed the intake valves cleaned (a very costly job) after just 54,000 miles. I understand many manufacturers ...

Yes. Because the fuel/air mix is directly injected, it does not enter the combustion chamber via the inlet valves and does not clean them. As a result, carbon can accumulate on the inlet valves.

Gasoline direct injection, or GDI, is one of the most crucial bits of technology in the modern internal combustion engine. In engines equipped with GDI, highly pressurized gasoline is sprayed directly ...