Rough idle when in gear

[Pipelayer]

2020 3500 has an intermittent rough idle when sitting at a stop in gear. You can feel it surging. Very strange. Cant identify a pattern of when it does it. 

[Tomato]

41 minutes ago, Pipelayer said:

2020 3500 has an intermittent rough idle when sitting at a stop in gear. You can feel it surging. Very strange. Cant identify a pattern of when it does it. 

Duramax???

[Pipelayer]

Yep. Sorry. Should have said that

[Pipelayer]

Vehicle has 22000 mostly towing miles on it. The roughness went away for about a month and just came back again. Going to have to take it in I guess. No codes or check engine lights. 

[Tomato]

2 hours ago, Pipelayer said:

Vehicle has 22000 mostly towing miles on it. The roughness went away for about a month and just came back again. Going to have to take it in I guess. No codes or check engine lights. 

I'd guess fuel filter or something with fuel supply (fuel pump, injector)...

[ssowie]

Could be in regen mode. Is the idle higher when you feel it?


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[cdnSpinalTap]

On 6/7/2020 at 12:05 PM, Pipelayer said:

2020 3500 has an intermittent rough idle when sitting at a stop in gear. You can feel it surging. Very strange. Cant identify a pattern of when it does it. 

I had this exact same issue with my 2016.  I felt it was a safety issue - if I took my foot slightly off the brake the truck would actually surge forward.  If I was slowly creeping forward into a parking space or garage, it was a little nerve racking. Dealer had no idea what it was.  Like yours, it was intermittent.

 

When I sold the truck, I fully disclosed the issue to the buyer.  Supposedly he had a diesel mechanic friend that said this was typical of these diesel trucks that have mostly city miles on them (which mine did, but sounds like yours does not).  He said they just needed a good manual regeneration to clean them out.  I have no idea if that is true or not, just relaying what he said.

 

Sorry I cannot be of more help - but thought I would mention that I had something similar.

[Dhamilton07]

@Pipelayer  Did you ever get this issue resolved or figured out?  My truck, 2020 Duramax w/31K was doing the same thing you described today.

 

Thanks!