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 ...

Direct injection. Just about every car has it now, and those that don’t probably will in the next few years. It can add power, reduce emissions, and is a big part of why just about everybody is ...