Rxgolfer

Bought 2021 Silverado 2500 HDlast Feb. Engine light on 3x first month various minor issues. Ran fine for 3 months or so. Now for last couple months get engine light , parking brake light, and traction light symbol, along with reduced engine power. Reset by dealer, then by myself with code reader ( code p0191) as happened more frequently, while waiting for backordered ecm. ECM replaced 2 days ago. Ok x1 day, now exact same problem engine light, reduced power etc. Back at dealer now. Any ideas? Thanks for any help.