Duramax 3.0 runs rough at low RPMs

[bigfarmerdave]

I’ve got a 2021 Silverado with the Duramax 3.0 that ran fine when I purchased it new. Once it hit about 3,000 miles, it didn’t seem to run as well. What I’ve found is there are times when driving down the street at an idle (1,000-1,400 RPMs) and you gently step on the accelerator, you can hear the truck shudder as well as feel it kind of shake. It feels like a dead spot on an old carbureted car where you’ve just got to try and push through it till you hit higher RPMs. Seems to do it about 20% of the time, typically between about 1,000-1,400 RPMs.  Started to notice it around 3,000 miles and it's got about 10,000 on it now so I've pretty well ruled out a bad tank of fuel.  Happens at low speeds (17mph) as well as higher speeds (45mph) but always at the lower RPM range.  I’ve had it to two dealers now and both said there were no codes and no bulletins issued on the problem so really nothing they can do. I guess I’m just kind of looking for suggestions or similar experiences.

[redwngr]

They can contact GM for help.  

 

Clearly, what you are describing is not the way it should run.  

 

I've put about 23K miles on mine. 

I don't think it's ever acted like you are describing. 

 

Back of the OM lists 'escalation steps to follow if you're not getting help from your service advisor.