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2021 Silverado 6.2 rough idle ?

Rcfire
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Rcfire Enthusiast

Rcfire

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Posted (edited)

So new here and have a question.  I have a 2021 Silverado with the 6.2.  It runs great but at idle at stop lights etc it has a rough idle almost like a misfire.  I have the afm turned off and it is not equipped with the auto start stop.  I have taken it in to the dealer and the dealer says can not duplicate but it’s very obvious.  I only run 93 octane fuel.  Truck has 4000 miles.  Is this a sign of a lifter failure coming in the future ?  Do these trucks  just idle like this ?  Any help ? 

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JAEDEE
JAEDEE

Bought my truck brand new with 5 miles on it.  I mentioned it to the dealer when I test drove it.  He told me they "all do it".  26k miles later and it stills does it, but I'm not worried about it bec

Z45
Z45

2021 Sierra Denali 6.2L and it idles so smooth you can't tell its running.  10,000 trouble free miles since 12/07/20....   I been adding a bottle of this every tank full for the better of th

Rcfire
Rcfire

Yes I only run 93 

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Robby James Enthusiast

Robby James

Posted
Posted

Mine idles like that, I am just getting the high pressure fuel pump replaced under warranty and am hoping this resolves the issue, but I doubt it.

Rcfire Enthusiast

Rcfire

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Posted (edited)

Keep me posted.  How did you get them to at least do that.  When I took mine in they act like they can’t feel it 

Edited by Rcfire
GETGONE Enthusiast

GETGONE

Posted
Posted

The 6.2 has DFM, not AFM. How do you have it disabled? I'm guessing it's a post May build since you say it doesn't have auto stop/start.

Robby James Enthusiast

Robby James

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On 10/2/2021 at 9:04 PM, Rcfire said:

Keep me posted.  How did you get them to at least do that.  When I took mine in they act like they can’t feel it 

Puddle of petrol pics on garage floor...lol

Of course they could not replicate leak on rack so I had to mention wife and son having headaches from the gas smell and that theybetter find something to fix.

Praying this was the culprit, post is below yours.

Mudcon Enthusiast

Mudcon

Posted
Posted

It is normal for the 5.3 and the 6.2.  They all have the rough idle you feel at stops.

Z45 Senior Enthusiast

Z45

Posted
Posted

2021 Sierra Denali 6.2L and it idles so smooth you can't tell its running.  10,000 trouble free miles since 12/07/20....

 

I been adding a bottle of this every tank full for the better of the 10,000 miles.  My nephew took one of mine and added to his wife's Cadillac SRX (75,000 miles) and it starting running smoother overnight to the point he bought a couple cases and adds it to every tank in the SRX and his Ecoboost Edge.

 

UCLCN_300px.gif

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Robby James Enthusiast

Robby James

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Posted

Mine is at idle when  in gear, feels like a distinct miss been that way since new.

13k on it now.

Rcfire Enthusiast

Rcfire

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10 hours ago, GETGONE said:

The 6.2 has DFM, not AFM. How do you have it disabled? I'm guessing it's a post May build since you say it doesn't have auto stop/start.

Yes I am sorry 

 

10 hours ago, GETGONE said:

The 6.2 has DFM, not AFM. How do you have it disabled? I'm guessing it's a post May build since you say it doesn't have auto stop/start.

Yes DFM I am sorry. I have it disabled with the pulsar 

Rcfire Enthusiast

Rcfire

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11 hours ago, GETGONE said:

The 6.2 has DFM, not AFM. How do you have it disabled? I'm guessing it's a post May build since you say it doesn't have auto stop/start.

Yes I am sorry DFM.  I have it turned off with the pulsar 

 

11 hours ago, GETGONE said:

The 6.2 has DFM, not AFM. How do you have it disabled? I'm guessing it's a post May build since you say it doesn't have auto stop/start.

Yes DFM I am sorry. I have it disabled with the pulsar 

Edited by Rcfire
Rcfire Enthusiast

Rcfire

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1 hour ago, Black02Silverado said:

Mine is a smooth idle. 

 

Not starting anything but do you run 93 octane?

Yes I only run 93 

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Rcfire Enthusiast

Rcfire

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1 hour ago, elcamino said:

2021 Sierra Denali 6.2L and it idles so smooth you can't tell its running.  10,000 trouble free miles since 12/07/20....

 

I been adding a bottle of this every tank full for the better of the 10,000 miles.  My nephew took one of mine and added to his wife's Cadillac SRX (75,000 miles) and it starting running smoother overnight to the point he bought a couple cases and adds it to every tank in the SRX and his Ecoboost Edge.

 

UCLCN_300px.gif

Thank you I will try that 

Rcfire Enthusiast

Rcfire

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1 hour ago, Robby James said:

Mine is at idle when  in gear, feels like a distinct miss been that way since new.

13k on it now.

That is exactly how mine is.  Have you ever had it in the shop for them to look at that ?  I just hate dealing with the dealerships but dang it’s drives me nuts when it does that.  I feel like a brand new truck should idle smooth 

Black02Silverado Senior Enthusiast

Black02Silverado

Posted
Posted
7 minutes ago, Rcfire said:

Thank you I will try that 

I run it as well in my Silverado and wifes Suburban.

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