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 Hyundai and Kia have been rolling out impressive new EVs like the Ioniq 5 N and Kia EV9 and redesigning existing models like the Sonata, the automaker still has the lingering problem of bad ...

Carbon buildup can create some big issues while you're driving. A few engine parts are more susceptible to it than others, so ...