Reduced power warning, engine light on

[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.

[CT Chevy Connoisseur]

May not be the same but my 2018 Mailbu just had a similar issue, the problem with mine was related to the gas pedal assembly and sensor.  It was replaced and now no more issues.

[Tomato]

On 8/13/2021 at 8:00 PM, Rxgolfer said:

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.

DMax or gasser?  Either way, when I Google that code, it talks about the fuel rail pressure / pressure sensor.  Has the dealer looked at that?