3.0 engine vibrations at idle

[E22MT406]

Hi all,

I’m new to the forum and also to the 3.0 Duramax. I traded my 18 canyon duramax in last December for a 2021 1500 elevation. I love the truck and I am trying to learn what is normal for this specific engine. My truck was purchased new and currently has 3800 miles on it. I’ve noticed that when my truck is at idle, it will sometimes vibrate/shudder, while stopped at a light or parked. The issue isn’t throwing any codes and the MyGMC app shows no diagnostic issues. The problem seems to be intermittent. It doesn’t always do this. I took it in to the dealer for this, and another issue (exhaust in cab), and there was no fix for either. I feel the idle is rough sometimes all though the RPM’s are stable on the dash. Does this seem normal for any of you seasoned 3.0 owners? Thanks all, in advance.

 

[CoyoteJackson]

Mine does the same thing at 29k miles and has since new. I don’t notice it doing it while sitting at a stop light in Drive but if I’m idling in Park, it’s definitely noticeable.

 

[E22MT406]

Thank you for your reply. I’m unsure of the temperament of these inlines, so I am unfamiliar with what may or may not be “normal” sounds, feels, etc. I do notice it more, when it happens, in park as well.

 

[Sperbonzo]

This probably sounds like a dumb question, but when the auto shut-off stops and re-starts the engine, it causes a shudder. Could that be what you are feeling?

 

[E22MT406]

This probably sounds like a dumb question, but when the auto shut-off stops and re-starts the engine, it causes a shudder. Could that be what you are feeling?

Hi, there. It’s definitely not the auto start. I turn my auto stop off as soon as I start my truck. I never use it. I still haven’t figured out why it occasionally does this.