Sounds like one of those energy drinks. And in a way, it is. It’s the new ingredient BP is touting in its gasoline to clean intake valves to keep your engine humming. Though we don’t know exactly what ...

The other day I dropped my car off at a European specialist shop, and while I was there, a technician was working in the engine bay of a Mk7 Golf R, cleaning out carbon deposits off the intake valves.

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 ...