6.2L Rough idle and poor low RPM response

[tj40371]

Our 2023 exhibits the same characteristics from time to time, but much more prevalent in the first few thousand miles (like nearly all the time). Dealer never found anything wrong and now at 17000 miles it is mostly smoothed out.

 

[apex944]

Our 2023 exhibits the same characteristics from time to time, but much more prevalent in the first few thousand miles (like nearly all the time). Dealer never found anything wrong and now at 17000 miles it is mostly smoothed out.

Thx, good to know. I'll have dealer take a look and then cross my fingers if they dont fin anything.

 

[jbooose]

I experienced the same rough idle issues you described when I took delivery of my 2021 Yukon Denali. It was definitely a rough idle and you could feel the engine and car slightly vibrate/shake. It did not occur all of the time though and I always used the correct octane fuel. If I applied just a bit of throttle to raise the RPMs up by about 100-200, it went away.

Dealer looked it over but said because there were no codes there was nothing they could do. They also told me they could not adjust the idle speed without a real "issue".

I now have about 34K miles on it and it rarely, if ever, happens now. Hopefully yours will go away too as seems to have happened with me and others.

 

[apex944]

I experienced the same rough idle issues you described when I took delivery of my 2021 Yukon Denali. It was definitely a rough idle and you could feel the engine and car slightly vibrate/shake. It did not occur all of the time though and I always used the correct octane fuel. If I applied just a bit of throttle to raise the RPMs up by about 100-200, it went away.

Dealer looked it over but said because there were no codes there was nothing they could do. They also told me they could not adjust the idle speed without a real "issue".

I now have about 34K miles on it and it rarely, if ever, happens now. Hopefully yours will go away too as seems to have happened with me and others.

Thanks. I just did my first real "tow" this past weekend. 20' steel enclosed with car. About 5500-6000 lbs I would guess. At lower RPMs (even way above idle) it does feel rough. Just doesnt feel smooth at all with part throttle loads.

 

[WalleyeMikeIII]

Thanks. I just did my first real "tow" this past weekend. 20' steel enclosed with car. About 5500-6000 lbs I would guess. At lower RPMs (even way above idle) it does feel rough. Just doesnt feel smooth at all with part throttle loads.

It is possible this is transmission shudder vs. engine...worth taking it in and ask service manager to take a ride w/ you.
Techs can hook up diags and drive it, or have you drive it, and monitor things...Misfires are reported as are fuel trims, and a bunch of otther stuff...

 

[apex944]

Yup, its time to gather some real data.

 

[JVega]

Just took delivery of a brand new 2024 Yukon Denali.
Immediately upon pulling away from the stealership I noticed what appears to be a slight misfire at idle and a very slight hesitation upon throttle take up in drive. I'm pretty familiar with engine tuning as I race cars where I program the ECU... so really dont think it is my imagination. I dont think its a complete cylinder miss but more like an intermittent or weak fire. I have no diagnostic tool for this engine (yet). Didnt think I'd need it yet. LOL.

So my question is... has anyone experienced such a low RPM miss ?

Also, I think I know the answer but is there any 3rd party software to (permanently) turn off the damn auto engine start? It jerks so bad when pulling away from a light that I spilled my coffee all over. (yes even when barely giving it throttle). I actually do wonder if the low RPM problem noted above is causing the autostart issue.

I have a 2023 Yukon Denali, with the 6.2L engine. I was told this engine hesitation is caused by the DFM (Dynamic Fuel Management system). On my older 2019 Yukon Denali I never noticed the hesitation. On my new 2023 I have noticed it quite a few times, it normally lasts a second or two. The first few times it scared me thinking the engine was going to stall or something. My truck has a bit over 5000 miles. The DFM is what shuts off several cylinders at a time if not needed to save fuel. I wish there was a way to disable it, but it does not seem possible. My 2019 also had the 6.2L but I am not sure if it had DFM, or the older AFM (Active Fuel Management). The reality is, we but these trucks with the big V8 engines to have all the power possible at all times, I wished the government did not force the manufacturers to create all this BS which diminishes the beautiful V8s.

 

[ChrisYukon]

I had an occasional rough idle in my '17 Denali. The dealer ended up replacing the engine mounts at 30,000 miles under warranty, and it never happened again. It was a problem they were searching for at every service.

 

[apex944]

After driving for another 300-400 miles I can say that its usually more of a transmission issue. The 1-2 shift is consistently poor.
Even with the slightest of throttle applications (which I realize these days is not just the TPS and my foot, but an algorithm) it go 1st THUNK 2nd. Jerking relatively hard as 2nd engages.
I did speak with the dealer and one of the service managers said his 6.2L did the same thing. He was just living with it.
Hopefully the trans ECU learns over time as some suggested it might.

 

[KMeloney]

I’d say that mine might do the same. Not so much a thunk, but it’s not particularly smooth. The whole trans is better than my ‘09’s, though, so I’m ok with it (for now, anyway).