Dealer not honoring warranty work..2018 5.3 Yukon issues

[Sarah_279]

Interesting observations from last night's 2020 LT 4x4 brand new test drive. Drove the truck for 10 mins at 50+ MPH, came to the stop kept in idle in D and even after a minute in idle look at the idle RPMs - malfunction or ECM still learning?
View attachment 236532

Hmmm.. Here's mine: this is fully warmed up, premium top tier fuel... I have a '19 though, so maybe that won't help you. But, for what it's worth -- ?

 

[smokey_mountain]

Thank you, this is about where mine sits in idle when it misses. So it sounds like that 2020 LT that I drove and saw it idling at ~700 was an anomaly.

Hmmm.. Here's mine: this is fully warmed up, premium top tier fuel... I have a '19 though, so maybe that won't help you. But, for what it's worth -- ? View attachment 236700

 

[HiHoeSilver]

Seem fine to me. Was that a drive or just idling and raising the rpms in park? Have you checked your grounds and the battery cables? It's common for the trims to be negative, up to -10 or so while idling and then it will attempt to get to zero and if you are driving at a steady speed for a while the computer will get there usually. Sometimes not but close. Depends on fuel, weather, driving habits, etc.

It was driving. I have checked the battery connections all seem to be tight. I thought about disconnecting every connection at the body but I will need to figure out which connections and wires to re-tighten.

I dont know. Seems wonky to me. I don't like how low they are. Looks like a downward trend over the course of the drive. I'm having a hard time visualizing the graph vs the rpms. Doesn't seem consistent to me. What do the o2 b1s1 and b2s1 graphs look like? Have you messed with or replaced the o2s?

 

[smokey_mountain]

@HiHoeSilver

I am trying to plot, everything is far in negative territory, I must be running rich?
No I did not touch o2s ever and I do not have plots for them but will add them to the BlueDriver logger for tomorrow.

 

[JC 707]

Hmmm.. Here's mine: this is fully warmed up, premium top tier fuel... I have a '19 though, so maybe that won't help you. But, for what it's worth -- ? View attachment 236700

I have a 2019 as well and this is my exact idle when warmed as well.

 

[calif phil]

That water bottle didn't look very shaky to me. I am thinking the dealership is right, nothing wrong!

 

[smokey_mountain]

Everyone who posted here saying their idle is glass smooth, they cannot detect the engine running. You can read through the thread. I can definitely feel the engine running because it shakes, throbs and flutters. Thus I posted a video. Curious if someone with the glass smooth idle can post their bottle tests.

That water bottle didn't look very shaky to me. I am thinking the dealership is right, nothing wrong!

 

[swathdiver]

Everyone who posted here saying their idle is glass smooth, they cannot detect the engine running. You can read through the thread. I can definitely feel the engine running because it shakes, throbs and flutters. Thus I posted a video. Curious if someone with the glass smooth idle can post their bottle tests.

Who wants a glass smooth idle? I bought an LS man! Just funnin' ya Dmitry!

 

[smokey_mountain]

@swathdiver Just plain awesome sound even on the video! I understand when that beast rough idles, it pays off in a very different way.

 

[91RS]

Everyone who posted here saying their idle is glass smooth, they cannot detect the engine running. You can read through the thread. I can definitely feel the engine running because it shakes, throbs and flutters. Thus I posted a video. Curious if someone with the glass smooth idle can post their bottle tests.

I don't really see how anyone could say they can't detect the engine running at all. I was going to do your water bottle test in a few trucks including my own (2008 and 2012) just out of sheer curiosity but I don't drink bottled water so I've got to get a bottle for demonstration purposes.