Dealer not honoring warranty work..2018 5.3 Yukon issues

[smokey_mountain]

For the "fun" of it, GM keeps replying with the same canned replies, but this time from their so called escalation email [email protected] but note it is the same person writing who responded earlier with exact same statement. I will trying calling now but from reading, call center will not overrule what email support did...

For $50K, I am jumping through all the hoops and getting nowhere. If there is a good advice on the attorneys, I think I would. Small court does appear to be an option here.



Begin forwarded message:

From: [email protected]
Subject: RE: [EXTERNAL] Re: Re: Re: Help with rough idle diagnostics...
Date: November 15, 2019 at 10:53:30 EST
To:
Reply-To: [email protected]


Good morning. Please know, both GM and Hendrick dealership thoroughly reviewed and exhausted all resources available to resolve the concern with your vehicle. It was determined your vehicle is operating as designed. I understand this is not the outcome you were expecting and apologize for any inconvenience this has caused. If you have any other questions or concerns about this matter, we strongly encourage you to continue working with your dealership.

Chelsea T.

 

[smokey_mountain]

Thank you, @swathdiver appreciate your help. I am posting one more set of logs from today
with short and long fuel trims, if you can take a glance at them that would be so helpful.
I am running Top-tier gas only from Costco or Shell. Will do the dielectric grease this weekend and also will try to check the gap.

https://drive.google.com/file/d/1dIw-Sc9ftoAEe60nE40I1uerNL-VBlQZ/view?usp=sharing

Ok, not finding a specific threshold before codes are thrown. However, the manuals do describe your exact conditions and suggest checking the fuel for contamination and the plugs and wires. If this were my truck, I'd run only Top-Tier high octane gasoline in it, then put dielectric grease on all spark plug ends which also makes sure they are all properly seated. I would also verify the gap on the spark plugs. Another thing mentioned in the book, was to make sure the injector harness was plugged into the right cylinders (no brainer right?) and misfires on 1 and 7 (2 and 6) could be an impending sign of an AFM problem coming up. Hope this helps Dmitry.

 

[smokey_mountain]

Is it worth replacing spark plugs and wires? to get to them I need to take wheels off and remove the wheel arc covers. It is still cheaper than trading it in, but in the course of the diagnostics I am already $350+ into it...

Any thoughts on this snake oil https://www.amazon.com/gp/product/B07PXCTPV7/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

 

[iamdub]

Try a different brand of fuel? I'm not a fan of Shell. I have no scientific data to back up my claim, but I swear I get better MPG, more power and smoother operation on Chevron. I run 93 exclusively. Maybe run your tank to around 1/4, dump in a bottle of Berryman B-12 and run it to 1/8 - 1/16 and fill up with Chevron 93.

 

[swathdiver]

Thank you, @swathdiver appreciate your help. I am posting one more set of logs from today
with short and long fuel trims, if you can take a glance at them that would be so helpful.
I am running Top-tier gas only from Costco or Shell. Will do the dielectric grease this weekend and also will try to check the gap.

https://drive.google.com/file/d/1dIw-Sc9ftoAEe60nE40I1uerNL-VBlQZ/view?usp=sharing

Assuming cell CE is for Bank1, that side is running about 75 degree hotter (cat temps). Then I see that the fuel pump commanded and actual fuel pressures are not matching up more often than not. Mine always do.

Don't run either of those fuels. Shell is just no good. I can always count on Shell to deliver 2 mpg less than Mobil, Sunoco and Chevron, every time and that's with their 93 octane even. Costco is top-tier but where'd they buy it from? Shell?

Do yourself a favor and switch over to Chevron or Mobil for a couple of tanks and see if the motor settles down. Texaco and Exxon are affiliate of each and I know they are up there in North Carolina. What part? I like Winston-Salem, Greensboro and Wilmington/Wrightsville Beach. It's been my pleasure to help, you're welcome!

 

[Miami-Dade]

.
I am running Top-tier gas only from Costco or Shell.

https://drive.google.com/file/d/1dIw-Sc9ftoAEe60nE40I1uerNL-VBlQZ/view?usp=sharing

Don't run either of those fuels. Shell is just no good. I can always count on Shell to deliver 2 mpg less than Mobil, Sunoco and Chevron, every time and that's with their 93 octane even. Costco is top-tier but where'd they buy it from? Shell?

Do yourself a favor and switch over to Chevron or Mobil for a couple of tanks and see if the motor settles down. Texaco and Exxon are affiliate of each and I know they are up there in North Carolina. What part? I like Winston-Salem, Greensboro and Wilmington/Wrightsville Beach. It's been my pleasure to help, you're welcome!

Do what James said. I used Shell during a Hurricane cause I had no choice. I got 12 MPG instead of the 24 MPG out on the highway. Plus my Tahoe ran horribly.

I hope nobody on this forum uses Shell or Costco.

 

[HiHoeSilver]

Is it worth replacing spark plugs and wires? to get to them I need to take wheels off and remove the wheel arc covers. It is still cheaper than trading it in, but in the course of the diagnostics I am already $350+ into it...

Any thoughts on this snake oil https://www.amazon.com/gp/product/B07PXCTPV7/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Agree with James, Chris, and Gary on the fuel. Screw Shell. I use exclusively Mobil or BP stations now (unless I'm on e85), and the mpg shows it.

I will look through your logs closer this evening, but at first glance you dont have a vac leak. Your trims seem to be low, if anything. Can you see the alcohol % somewhere?

New plugs and wires would be my first move with a misfire count like that. Relatively "cheap" and easy to rule out by changing.

If you want to run a real fuel system cleaner, do yourself a favor and get some Kreen from www.kanolabs.com

 

[smokey_mountain]

Thank you everyone for all the help! Much appreciated, if it was not for support from this forum, my kids college would be delayed as I will be still paying off trade-in vehicle

I have problem with my knee and cannot stand on knees for a long time to change spark plugs, but I will check wires and put dielectric on the plug boots.

 

[GTNator]

Do what James said. I used Shell during a Hurricane cause I had no choice. I got 12 MPG instead of the 24 MPG out on the highway. Plus my Tahoe ran horribly.

I hope nobody on this forum uses Shell or Costco.

Interesting, I dint know Shell was so bad. They must add additives to their fuel that are different than what others add to make it their own proprietary blend cause other than that, they’re all the same. I wonder what crap their mixing in there? But noted, I will make a point of not going to Shell; I don’t think I ever do but that was due to Mobile and Chevron being closer.


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[HiHoeSilver]

After looking at your logs a little, without going back through the whole thread, have we talked at all about your idle simply being a little low? It's barely at 500 on average. I'd be happier to see it around 6, and that 100 rpm can make a huge difference in the typical Chevy "rough" idle.