Mopar’s official brown foaming spray has worked very well for me, including on heavily carbon’ed up EGR passageways.
It makes a huge cloud of black smoke.

https://www.morris4x4center.com/mopar-combustion-chamber-cleaner-13-oz-aerosol-can-4318001ad.html

As an experiment many years ago I used a second pcv valve to suck ac conditioner drain water into the intake manifold of a 1995 Magnum 5.9 V8 for over two Summer months. This made an odd noise in the passenger compartment of the pickup, slightly lowered city MPG, but did clean carbon off the tops of pistons.