Consumer Reports has no financial relationship with advertisers on this site. The process of walnut blasting, which entails cleaning the intake manifold and valves of a car’s engine with a high ...

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.

While carbon buildup happens on essentially all engines, gasoline, diesel, N/A, or boosted, it's an increased concern in GDI engines. Standard Electronic Fuel Injection features injectors higher in ...