Direct Injection carbon intake valve cleaning

[hardwang]

doc, even if you do the italian tune up on a DI engine. it wont help as the injectors are past the intake valves. Toyotas and some fords have dual injection (port and direct injection)to fixed this issue. while some hyundais&kias have gone back to port injection instead of GDI(direct injection).

That is true. Fuel won't reach the back of the intake valves, therefore there won't be anything to clean it.

The theory behind italian tune up for DI as I recall, is that "supposedly" you run the engine hard long enough so that the engine produces enough heat to melt the carbon deposits off. I'm not entirely convinced that its enough or it even works at all.