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.

Fuel injectors don't just deliver fuel. They meter it, shaping the spray so the air-fuel mixture burns in the way the engine wants it to. When deposits build up, injector fuel flow can decrease and ...

Fuel injectors can get gummed up with dirt and fuel residue over time. Photo credit: David Traver Adolphus / Autoguide.com. Over time and miles, your car might start to slow down. It might not ...

Shutterstock // Setta Sornnoi Over time and miles, your car might start to slow down. It might not accelerate as quick ...

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 ...

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 ...