Great pic, one can see how the buildup hinders airflow into the cylinder over time.
I have used Subaru Upper engine cleaner for about 15 years on too many cars to mention. Wonderful product.
When I get a complaint vehicle, I strip the intake manifold on a hot engine, I fill the intake port on cylinders that have valves closed, wait 5 min, turn the engine to do the other cylinders, reassemble intake, start engine, run another 1/2 can through the intake at the throttlebody, smoke the workshop out
, roadtest the car at mid to high rpm and load until the smoke clears.
AC Delco also make combustion chamber cleaner, which appears to be the same product.
Obviously Toyota sees a problem, and are trying something to fix it.
Direct injection came about to meet Euro 5 emission standards.
It will interesting to see if Toyota can still meet Euro 5 with an outboard injector.