Stumble/Hesitation AND stalling continuation thread

[HD_LS]

We are having this exact issue with a 2013 Yukon XL Denali (6.2) we're looking at - currently have it on a 24hr test drive. I'm very interested in any follow-up thoughts about the root cause.
- Sam

Don't buy it! That's probably why it was sold/traded in. Many things can cause those symptoms, including some very major problems. Don't knowingly buy someone else's problem.

 

[bdbull]

Let us know how it works for you.

I've mentioned this procedure three or four times over the last six months, and no one ever reports back.

I can confirm that this procedure keeps the truck from going into V4 mode, but I'm still having transmission issues. I've kinda put this problem on hold to do the oil pan gasket replacement...which is not fun so far.

 

[Charlie207]

I can confirm that this procedure keeps the truck from going into V4 mode, but I'm still having transmission issues. I've kinda put this problem on hold to do the oil pan gasket replacement...which is not fun so far.

Thanks for checking in.

Good luck with your transmission issues, and the oil pan gasket.

 

[Mad-Max]

Don't buy it! That's probably why it was sold/traded in. Many things can cause those symptoms, including some very major problems. Don't knowingly buy someone else's problem.

well, ok, but I still have not read which specific causes are 'actually' causing this exact problem; after reading every related thread I still have not seen conclusive 'this was it - and this is what fixed it' solutions. This idle 'stumble/miss' we're having is very slight, averaging about 1 instance per 10 seconds, with an associated 'click/tick' audible from the front fender well, and unfortunately, no codes (two videos below). It has got to be 'something', and I've yet to rear of anyone actually solving the problem. We have a 30-day return option with this one, and if Carmax can or won't resolve it, we may buy it anyway, take it to out mechanic (like us a live-long hot-rodder who knows old and new tech), and try to resolve it ourselves within that 30-day return window. If we can, cool, if not we can return it.

Shared album from Sam 📸

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Shared album from Sam 📸

Tap to view!

photos.app.goo.gl

 

[Mad-Max]

Lemme ask this - if the issue for the 'bouncing idle' is 'bad lifter(s) as a result of the AFM/DOD systems' (and I'm not saying it is), if I find a Yukon that idles perfect and does not have the misfire, and if I were to upload the software to disable the AFM/DOD systems, would the possibility of the lifters going bad then be 'eliminated', or can those respective lifters still go bad? I know there are no absolutes, but just wonder if the DOD system cycling into/out of 4-cyl mode is 'the cause', and if it's eliminated would the hardware endure...

 

[Mad-Max]

here's another question. 2013 Yukon XL 2500 (6.0) - AFM?, or not? I've read the iron block 6.0's do not have it. Can anyone confirm that?

 

[Mad-Max]

I was going to test-drive the Denali again, drop it in manual mode and see if the idle miss goes away, but I read that V4 mode/AFM does not happen at idle. Add all the negative reviews about the AFM/DOD systems being basically a situation of 'not if, but when', so we're bailing on this Denali.

And because we're now after a 2500, we're also bailing on further digging into what the engine miss is - at least for now, and I apologize to anyone that's read this thread this far only to get no answer because I normally don't let questions I ask go unresolved, but if I come across solid intel I'll post back.

Hopefully, in about a week I'll post a new thread about our 'new' 2500 . While we really loved how the Denali drove, according to the codes it had 3.42s, and the 2500 we're looking at has 3.73s, and hopefully the lower gears will offset the lower performing 6.0, and the truck will 'feel' just as peppy as the Denali did. Meh - even if it is a bit less 'sporty' I'm sure it'll boogie down the road with authoritahhh.

 

[bdbull]

Possibly made a breakthrough on this issue. Threw two codes today: P0300 and P0301. Threw P0300 at startup and then I'm assuming P0301 was thrown later bc the CEL flashed a few times when I took off from a stop light. Hoping to be able to pull the plugs and take a look at them this weekend.

 

[bdbull]

Just pulled plugs 1, 3, and 5. All three looked awful. The tip was so worn down that they were all gapped over .08. I re-gapped the three I pulled to .04 and put them back in. Started the truck up and it actually ran a little bit better right off the bat. I'm guessing I'll just replace them all since they probably all look like that now. The manual calls for 41-110 which are iridium, but I'm wondering if I should go with something different. I put these in 20k miles ago and they apparently haven't faired very well. Anyone got any opinions on that?

Btw, how in the world does the tip get worn down like that?

 

[Doubeleive]

Just pulled plugs 1, 3, and 5. All three looked awful. The tip was so worn down that they were all gapped over .08. I re-gapped the three I pulled to .04 and put them back in. Started the truck up and it actually ran a little bit better right off the bat. I'm guessing I'll just replace them all since they probably all look like that now. The manual calls for 41-110 which are iridium, but I'm wondering if I should go with something different. I put these in 20k miles ago and they apparently haven't faired very well. Anyone got any opinions on that?

Btw, how in the world does the tip get worn down like that?

not sure but I drive the literal piss out of mine and I know my plugs that are around 50k or so are not worn down, where did you buy the plugs? there are a lot of fakes out there and they can cause problems.
as far as the clicking noise on the passenger side the only thing that would be clicking over there is the ac pump, try taking the ac belt off and see if you notice any change, you can just leave it dangling it wont hurt anything.
simple little things like changing the plugs/wires and doing a injector service or running a few bottles of injector cleaner for a while can clear up that kind of issue it doesn't sound nor appear to be anything detrimental at all, a little tlc and she should be fine.

 

[Doubeleive]

I went back and looked and I see already mentioned what I just said again right off the bat, I am assuming none of that was performed, it won't just fix it's self

 

[bdbull]

I think the clicking noise comment was for someone else.

I got the plugs from Amazon. Maybe they weren't authentic AC Delco bc if I click on the link in my order history the page doesn't exist anymore. I think I might go with some NGK plugs this time - https://smile.amazon.com/NGK-Laser-...1&qid=1638667544&sprefix=IZTR5,aps,195&sr=8-3

 

[Geotrash]

I think the clicking noise comment was for someone else.

I got the plugs from Amazon. Maybe they weren't authentic AC Delco bc if I click on the link in my order history the page doesn't exist anymore. I think I might go with some NGK plugs this time - https://smile.amazon.com/NGK-Laser-Iridium-Spark-IZTR5B11/dp/B00PMEMPM0/ref=sr_1_3?crid=3QYTRD9N8SE0Q&keywords=iztr5b11&qid=1638667544&sprefix=IZTR5,aps,195&sr=8-3

I would buy the OEMs but from Rock Auto this time.

 

[bdbull]

I would buy the OEMs but from Rock Auto this time.

That's a great idea. Looks like they have a rebate promotion going on too, so they will be even cheaper.

 

[OR VietVet]

That's a great idea. Looks like they have a rebate promotion going on too, so they will be even cheaper.

I have a $25 gift certificate code that you can use. Got it with promotional materials for a car show supplied by RA

CODE: CF2D1828A7B690 Good till 12/31/21

 

[Doubeleive]

I think the clicking noise comment was for someone else.

I got the plugs from Amazon. Maybe they weren't authentic AC Delco bc if I click on the link in my order history the page doesn't exist anymore. I think I might go with some NGK plugs this time - https://smile.amazon.com/NGK-Laser-Iridium-Spark-IZTR5B11/dp/B00PMEMPM0/ref=sr_1_3?crid=3QYTRD9N8SE0Q&keywords=iztr5b11&qid=1638667544&sprefix=IZTR5,aps,195&sr=8-3

ya I see now someone else tossed there mess in the comments, you have to be careful buying off amazon unless it specifically states sold by amazon or acdelco and is claimed to be oem I wouldn't buy it, even the knock sensors I bought from acdelco on amazon looked questionable but they worked.

 

[bdbull]

I have a $25 gift certificate code that you can use. Got it with promotional materials for a car show supplied by RA

CODE: CF2D1828A7B690 Good till 12/31/21

I already ordered them, but thanks anyway. Maybe someone else can use it.

 

[bdbull]

Didn't realize I never closed out this thread.

The new set of plugs cleared up the issue right away. I'm hoping I just got some knockoff plugs from Amazon and that my engine isn't fouling plugs up that bad, that fast. I guess time will tell. Here is what the plugs looked like once I got them out. Notice none of them have that nice tip on them.

 

[kevlac]

Didn't realize I never closed out this thread.

The new set of plugs cleared up the issue right away. I'm hoping I just got some knockoff plugs from Amazon and that my engine isn't fouling plugs up that bad, that fast. I guess time will tell. Here is what the plugs looked like once I got them out. Notice none of them have that nice tip on them.

Still doing well?

 

[donjetman]

Didn't realize I never closed out this thread.

The new set of plugs cleared up the issue right away. I'm hoping I just got some knockoff plugs from Amazon and that my engine isn't fouling plugs up that bad, that fast. I guess time will tell. Here is what the plugs looked like once I got them out. Notice none of them have that nice tip on them.

what were the gaps?