Yes, The 4.2 Has A PCV System
It's a somewhat hotly debated stand that there is NO PCV system in the GM 4.2 Liter straight 6-cylinder engine in Trail Blazers and Voyagers and some Saabs I think.
Really --- the US Gummermint won't let an engine go out for sale without SOME way to clean the sump - commonly called "The Crankcase".
This is a somewhat non-technical examination of the visible - outward parts of the PCV - the KV (atmospheric side) and the CV (vacuum sourced side and final death to the fumes of the crankcase).
Here's my Official Stomping Grounds: https://www.trailvoy.com/