6.2L Rough idle and poor low RPM response

[StephenPT]

1st to 2nd is the biggest jump - It's the only gear shift I "feel" in mine with the LM2. Mine only has a bit of a "lurch," which is not bothersome. The rest of the gear shifts are completely imperceptible, outside of seeing/hearing the RPM change.

 

[Scarey]

2024 Tahoe 6.2 with 4000 miles always use 91. Always been a touch rough at idle. Took in for free oil change and asked the dealership to look at idle. They said no codes and was ok. Reading around the forums it seems there is agreement the idle is set too low from the factory, maybe causing a slight lean “misfire”. Overthinking it I decided to try ethanol free 92, ethanol blend has an extra oxygen atom, leaning it further? It idles allot better on the non-ethanol. Not perfect but better.

 

[iamlegion]

2024 Tahoe 6.2 with 4000 miles always use 91. Always been a touch rough at idle. Took in for free oil change and asked the dealership to look at idle. They said no codes and was ok. Reading around the forums it seems there is agreement the idle is set too low from the factory, maybe causing a slight lean “misfire”. Overthinking it I decided to try ethanol free 92, ethanol blend has an extra oxygen atom, leaning it further? It idles allot better on the non-ethanol. Not perfect but better.

When you say rough idle, does it sound, feel, or run rough? Does it hesitate when accelerating?

 

[Scarey]

When you say rough idle, does it sound, feel, or run rough? Does it hesitate when accelerating?

I’ll call it a slight stumble at idle, the tac will fluctuate 100rpm at idle. Don’t hear anything. Smother now, 1/2 of what it was. Next fill up will put me at 100% non ethanol. Curious how it idles then.