Intake valve cleaning methods on GM 3.6

[i6pwr]

Our 2015 Impala has 115K miles and I would like to run something through it for any necessary valve cleaning. I have done the 44K platinum about 10K miles ago but what is recommended here? I believe this engine gets a tiny bit of injector spray due to valve timing but I may be mistaken.

I still need to change the plugs, plan on that in the coming weeks. Engine runs smooth but has that infamous shake in park around 1500 RPM and barely a light vibration at idle, other than that it's smooth as silk on the highway with excellent MPG. We bought it used with 85K and still runs great plan on keeping it.
Is the CRC GDI IVD what I should use? What says the BITOG peers?

 

[JTK]

You don't hear of the various GM GDI 3.6's carboning up to the point they have issues. I would wait until you needed to pull the intake plenum off for a spark plug change to make that determination. You'll be able to see the intake ports/valves with the plenum off. No injector spray makes it across the valves on the GM 3.6s.

 

[GMBoy]

The more common issue of your shakes on those Impalas are motor mounts so check those first.

On my 3.6DI (CTS) I spray a can of whatever I have on hand (CRC DI Intake valve cleaner or carb cleaner lol) thru the intake with engine running. There is a small vac pipe I disconnect and spray there at about 2k rpm. Spray the whole can and shut car off an hour or so then run it thru the gears a couple times. It always seems to run smoother afterwards. I do this only before the oil change routine. I have had my intake off to replace the injectors at around 180k and things did not look pristine but they were not severe either so I can't say if my routine actually helps cleaning but I think it probably knocks some of the crud off atleast. I have had other DI 3.6's in with less miles that looked terrible in my opinion so that is why I still do the cleaning every oil change. I got 206k on her now and runs same as new.