Jump to content

2021 Silverado 6.2 rough idle ?

Rcfire
 Share

Recommended Posts

Z45 Senior Enthusiast

Z45

Posted
Posted

I can only buy 91 octane Premium around here,  93 is no where to be found. 

  • Replies 31
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

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 

Posted Images

JAEDEE Enthusiast

JAEDEE

Posted
Posted

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 because if it was something to worry about, it should have gotten worse over the miles and it hasn't changed a bit.  I live in California, so 91 octane is all we get.  may give the Amsoil stuff a try and see how it goes. 

  • Like 3
GETGONE Enthusiast

GETGONE

Posted
Posted

Disabled by the actual Pulsar LT or the Range AFM/DFM disabler? The AFM/DFM doesn't work on the 2019+ 10 speed trucks per their website: The AFM/DFM Disabler is NOT currently compatible with 2019+ 5.3L 10-speed or 6.2L 10-speed models.

lpg Enthusiast

lpg

Posted
Posted

I had the same question on my 6.2. Was about to run a “cleaner” through but checked fuel trims to see if injectors were dirty, after 40k miles, they’re nearly perfect…. So unless there’s some other fuel related issue, they probably just idle a little rough.

 

fwiw, my afm is disabled 

Rcfire Enthusiast

Rcfire

Posted
  • Author
Posted
On 10/9/2021 at 7:09 AM, lpg said:

I had the same question on my 6.2. Was about to run a “cleaner” through but checked fuel trims to see if injectors were dirty, after 40k miles, they’re nearly perfect…. So unless there’s some other fuel related issue, they probably just idle a little rough.

 

fwiw, my afm is disabled 

Ok thank you I might try some of that amsoil fuel treatment and see if that helps 

lpg Enthusiast

lpg

Posted
Posted
On 10/12/2021 at 8:29 PM, Rcfire said:

Ok thank you I might try some of that amsoil fuel treatment and see if that helps 

My point in writing was that the motor is running perfect if fuel trim is near zero.

 

not sure what may be causing idle to seem rough but I don’t think there’s any problems or any fuel related system to be cleaned. 

Rcfire Enthusiast

Rcfire

Posted
  • Author
Posted
22 hours ago, lpg said:

My point in writing was that the motor is running perfect if fuel trim is near zero.

 

not sure what may be causing idle to seem rough but I don’t think there’s any problems or any fuel related system to be cleaned. 

So I looked further into it and seems mine is the motor mounts.  I found a service bulletin out for it and says they are either faulty or need shims.  Taking it in Monday and I’ll keep everyone posted 

start2finish New Member

start2finish

Posted
Posted

Motor mounts don't help.  I had to show the dealer that the truck had rough idle when in gear.  They were observing in Park and it ran smooth.  Traded the day after motor mounts didn't fix it.  2018 GMC 5.3L 8peed 4wd.  Did the rough idle from 300 miles on.  They wanted me to pay to have the fuel system cleaned at 35900 miles.  I explained it was doing the rough idle on the first tank of fuel.

 

Currently have 2021 GMC with 3.0 duramax.  I have had enough of the GM gas engines. This one doesn't always start on the first try, but runs smooth as silk when its running.

Rcfire Enthusiast

Rcfire

Posted
  • Author
Posted
11 hours ago, start2finish said:

Motor mounts don't help.  I had to show the dealer that the truck had rough idle when in gear.  They were observing in Park and it ran smooth.  Traded the day after motor mounts didn't fix it.  2018 GMC 5.3L 8peed 4wd.  Did the rough idle from 300 miles on.  They wanted me to pay to have the fuel system cleaned at 35900 miles.  I explained it was doing the rough idle on the first tank of fuel.

 

Currently have 2021 GMC with 3.0 duramax.  I have had enough of the GM gas engines. This one doesn't always start on the first try, but runs smooth as silk when its running.

12 hours ago, start2finish said:

Motor mounts don't help.  I had to show the dealer that the truck had rough idle when in gear.  They were observing in Park and it ran smooth.  Traded the day after motor mounts didn't fix it.  2018 GMC 5.3L 8peed 4wd.  Did the rough idle from 300 miles on.  They wanted me to pay to have the fuel system cleaned at 35900 miles.  I explained it was doing the rough idle on the first tank of fuel.

 

Currently have 2021 GMC with 3.0 duramax.  I have had enough of the GM gas engines. This one doesn't always start on the first try, but runs smooth as silk when its running.

Did you have your motors mounts replaced ? And it didn’t help ? Ugh so frustrating.  Mine vibrates so bad when in park and in drive.  On the highways it’s smooth 

start2finish New Member

start2finish

Posted
Posted
On 10/17/2021 at 8:40 AM, Rcfire said:

 

yes, they replaced the motor mounts.  No difference.  Treating a symptom of the skip doesn't fix the problem.  I believe its a known issue that they don't consider to be a problem.  It was embarrassing when passengers noticed it.  Only issue that truck ever had, I was happy with it overall.  But I am glad its gone.

  • 2 weeks later...
Denali_Joe Enthusiast

Denali_Joe

Posted
Posted

I'm on my 3rd 6.2 since 08, this one is the smoothest (21 6.2) with foot on brake, but still has a little shake from time to time.  When I was getting the 08 tuned Justin mentioned to me that the truck is idling at some stupid low RPM and like lpg mentioned adding a little RPM will smooth it right out.  He added a little to show me and then went super smooth, but then set back to stock range.  If you leave the stupid stop/start on less shake time haha.

  • 3 weeks later...
Rcfire Enthusiast

Rcfire

Posted
  • Author
Posted
On 10/4/2021 at 8:33 AM, Black02Silverado said:

Mine is a smooth idle. 

 

Not starting anything but do you run 93 octane?

Yes I only

run 93 

  • Like 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • TrueBlue
      Wow I'm in a pickle. (Broke down truck) and a story.

      By TrueBlue · Posted

      I gotta say, I'm enjoying your narration. The troubles you've been having are amusing as you describe them. It's good to see that you're finally getting some satisfaction out the old beast though.
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      Declaring victory would upset the demons that possess this Blazer, so I won't. But I did make progress today--after it put up a fight. Always a fight.   I had the day off so I spent the morning cleaning up the shop and I thought I'd get ahead of things by filling the cooling system in prep for the final part I needed to arrive: the driver's side knock sensor. Glug, glug, glug....and then the unmistakable sound of liquid hitting the shop floor. It induces the same chagrin when the sonar and targeting laser temporarily malfunction during a late night bladder evacuation over the toilet with the bathroom light off. D'OH!!! That made a mess...   Oh, hey, that knock sensor I removed? It threads into a wet port. Who knew?! Learn something new every day. Put a pin in that chore, I'll fill it the rest of the way later.   The knock sensor arrived at about 1pm. I threaded it in, connected the wire, filled up the coolant, checked for leaks, and... drumroll.... fingers crossed for a perfect start, excellent timing, model fuel trims, and ...no squeaks... Here goes.....   No, it didn't start. At all. I cranked it a few times and it wasn't sounding good. Furthermore, I heard leaking again. Jesus H Tapdancing Christ, stop leaking all over the dang floor. This time I had accidentally overfilled the coolant reservoir and the churn of the water pump via cranking caused a bit to burp out. Ok, just, breathe... Put the flamethrower down. Dang thing wouldn't burn anyway, leaks too much...   Did you know the rotation of a round crank sensor in a round hole, matters? I do now. Took me about half hour to retrace steps and realize what I had done. Then it started right up.   No squeaks. The squeak was the old balancer.   Once it entered closed loop, fuel trims are dead on, hovering right around zero at idle. No more -30%. I'll credit the injector rebuild on that one.   Timing? I think there's an OBD 1.5 translation error with my Actron scanner. It's anywhere from -20 to -30 at idle, sometimes as high as -40 cruising. Sorry, the engine just isn't running that smoothly at -40 degrees ignition advance. It's just not. It's smooth all through the rev range and has decent power. I'm going to have to trust the seat of my pants on this one.   The new exhaust is very quiet. The old catalytic converter? Not melted, but definitely not healthy. Rains glitter when you turn it on its end...all the precious metal is flaking out. Once the new exhaust system burned in/smoked off a bit, the engine's exhaust smell is normal again. Not that I'd recommend going around huffing car exhaust, but, you know what I mean?   One problem to correct. The new exhaust has the opposite problem of the old spliced up exhaust. It wants to hit the floor where the old one wanted to rest on the cross member. Happy medium, please? Still noodling on that one, need to look at how I can adjust some hangers.   I don't know what's next. On one hand I want to run away from this thing as far and as fast as I can -- there have been a lot of NOT fun moments. On the other, now that it kinda drives nice, maybe drive it around for a little bit?   Shhh... it's not currently dripping oil all over the floor. I can see just a little wet at the bottom of the timing cover where it meets the oil pan seal. It's not dripping multiple drops with every ignition cycle, in fact, after some driving this evening it has yet to even form a drop that could drip off yet. But the weekend is young... I fully expect this could turn into Exxon Valdez by Sunday. Because this Blazer hates me. LOL.      
    • Grumpy Bear
      The Peckish Synapse

      By Grumpy Bear · Posted

      About that:   Once upon a time in a land far far away lived a car company that was shy about taking your money and wanted to be sure that they gave you more that you asked for so that you'd come back. No really, not a fairytale. 😱   But after the field got thinned out enough to limit the competition it seemed good enough to give you only what you asked for. Fair enough I say but in such a market you have to give something the others are not or they go to the one who does. Gimmicks or glitz. Oh, fins and chrome. Yea, shinny crow like cars. Yum.    Field narrows a bit more and 'brand loyalty' becomes a thing and the minute it does they start thinking to themselves, "Could we make more money if we gave them less than they expect and they will hang in there for brand and comfort with the known?" They gave it a try and da*n, it worked!!    Well, what if we teach them, groom them into believing that less is "Normal" and cut some more corners. Will that work? Oh heck yea!    🤔 I wonder, can we give then WAY less than they expect and make them mad enough to spit nails and STILL get them to pay up? Sure, if we get everyone else to do the same so that the choice is less or nothing at all. How would be do that? Platform sharing.  What a concept, right?  Steal like there is no tomorrow and it's legal too!    Truth is no one is going to give up driving, not for very long. The Gen Z crowd is fine with it and will be as long as someone not Gen Z will haul them around. At some point we all die.    Economic voting only works if you cast a NO vote now and again and enough of them to get dumb and dumber to wise up. Well, that's how I was taught anyway. And it should have worked. Would have worked. But the Bail out!!   Look, you have another choice if  you take that bag off your head. If the dumb it down to some predetermined expectation of how John Q Public will use it the, that is under design it to failure they you use it to a lower stress mode. D'ho!    A 1950 Royal Enfield Bullet 500 will go anywhere a Suzuki Hayabusa will and for just as long. But you will have to treat it for what it is and not for what you wish it was. 
    • Vu1can
      Bridgestone vs Goodyear tires?

      By Vu1can · Posted

      Maybe I was just too unlucky, but I had nothing but bad luck with Bridgestones. Out of 3 sets, they all started losing a lot of air when they got down to about 1/2 tread life, and at that point also wet traction suffered more than it should have. Also, the only tire I ever had in my 60 years of driving that had a side wall blow out was a Bridgestone.   I'm currently running Goodyear Wrangler Workhorse AT and am very happy with them.   
    • davester
      Broke Down on the Mountain

      By davester · Posted

      maybe when the trip is over, check all the other joints in the front end, like all the ball joints, tie rods, pitman & idler arms, etc...

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...