Dealer not honoring warranty work..2018 5.3 Yukon issues

[BG1988]

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While your point is rational, it is easier said than done, we saved up as a family for 3 years to buy our first "premium" vehicle - this Yukon, we are raising 4 boys, money matters. If I am to trade it in I would loose close to $10K after owning it just for 3 months, who knew that GM vehicles lose so much value on trade-ins. Two dealers told me there is nothing wrong with the vehicle, two independent reputable mechanics told me there is and plus 10+ misfires in $06 monitors on every ride.

Story with dealers is that they are only get paid if there are codes, no codes - stop troubleshooting per GM financial policy. This is exactly what one of the dealers told me "we cannot continue troubleshooting if there are no codes". There are dealers that are willing to do it on their own dime, but neither of the two that I met were at all interested. Will try Charles Boyd this Wed, they are known for their customer support. If they say no issues, then I would accept and move on, until then huge thank you to folks here that really cared to help me!

what is the current mileage? OBD2 codes are disabled tell the mileage hits certain amount..

how hot is the CAT running

it should be about 400 Celsius .. if it's like 700 to 2,000 Celsius it's burning raw fuel.. like I said you will need good proof go to a smog shop and have a probed test done... if it's failed they will let you know and you can make the dealer buy it back then ..

 

[91RS]

Story with dealers is that they are only get paid if there are codes, no codes - stop troubleshooting per GM financial policy. This is exactly what one of the dealers told me "we cannot continue troubleshooting if there are no codes".

I can tell you that is not true at all. Maybe another dealer can indeed help you.

My guess is still that you have an engine mount issue if there is really something wrong, your description along with no DTCs describes it perfectly.

 

[Bob2C]

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what is the current mileage? OBD2 codes are disabled tell the mileage hits certain amount..

how hot is the CAT running

it should be about 400 Celsius .. if it's like 700 to 2,000 Celsius it's burning raw fuel.. like I said you will need good proof go to a smog shop and have a probed test done... if it's failed they will let you know and you can make the dealer buy it back then ..

Hmmm I’m having same problem as OP but not as bad. I have had the motor mounts changed at 14k. Truck was good for a bit now it’s rough at idle again but not as bad. My cat temps are about 600 Celsius. Thoughts




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[smokey_mountain]

@BG1988 Truck is 9,080 miles only. My cat is running between 1300-1420F which is 700-760 Celsius. I will need to find a good smog shop in town, not sure how, but I will call them asking about probed smog test.

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what is the current mileage? OBD2 codes are disabled tell the mileage hits certain amount..

how hot is the CAT running

it should be about 400 Celsius .. if it's like 700 to 2,000 Celsius it's burning raw fuel.. like I said you will need good proof go to a smog shop and have a probed test done... if it's failed they will let you know and you can make the dealer buy it back then ..

 

[smokey_mountain]

Another 4 hours to see a dealer #3. I have to admit my truck is "normal" three dealers took a look at the truck and told me until there is a code, GM will not authorize a repair and they will not touch the vehicle. Misfires in S06 monitor means nothing to GM. Cats running at 760+ Celsius is within GM spec. Rough idle without a code is normal, no matter how rough the idle is. Once the code is thrown then they will clear it. They told me they cannot explain why it shakes but GM did tell them not to do mounts any more as shaking is normal operational condition of this truck and mounts do not eliminate it permanently and shaking will return as one owner here confirmed. They said that emission and SMOG fully passes. I will check with local SMOG facility if they can do probed test but I am sure dealer is confirming that emission is passing... as they know that I am relentless.

Time to start the search for a new vehicle.

 

[smokey_mountain]

I have called 6 local emission stations and all of them said that an only way to test emissions in NC now is via OBD II, probed machines are banned in NC as the last shop explained to me. I guess that is not an option any more for me either.

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what is the current mileage? OBD2 codes are disabled tell the mileage hits certain amount..

how hot is the CAT running

it should be about 400 Celsius .. if it's like 700 to 2,000 Celsius it's burning raw fuel.. like I said you will need good proof go to a smog shop and have a probed test done... if it's failed they will let you know and you can make the dealer buy it back then ..

 

[wjburken]

Another 4 hours to see a dealer #3. I have to admit my truck is "normal" three dealers took a look at the truck and told me until there is a code, GM will not authorize a repair and they will not touch the vehicle. Misfires in S06 monitor means nothing to GM. Cats running at 760+ Celsius is within GM spec. Rough idle without a code is normal, no matter how rough the idle is. Once the code is thrown then they will clear it. They told me they cannot explain why it shakes but GM did tell them not to do mounts any more as shaking is normal operational condition of this truck and mounts do not eliminate it permanently and shaking will return as one owner here confirmed. They said that emission and SMOG fully passes. I will check with local SMOG facility if they can do probed test but I am sure dealer is confirming that emission is passing... as they know that I am relentless.

Time to start the search for a new vehicle.

Before you write off your vehicle and take a hit in your pocket book trading it in for something, I would see what the mechanic that you trust would quote you to fix what he thinks needs fixing. In addition to that, you could look at getting a tune, although I think you mentioned that you were hesitant to do that. Both of these options, independently, or together, would likely be less than the loss you will take trading in and you will still have the premium vehicle that you wanted. I get that GM is not going to do anything under warranty without a code, but that doesn't mean you have to give up on the vehicle.

 

[smokey_mountain]

My wife agrees with you I promised her to try 4 things because she is mad at me for putting her into a time machine and transporting her into 1988 Yugo experience of a shaking car :
1) Mobil/Exxon gas (so far I am through the full tank but no change yet).
2) I will replace spark plugs and wires
3) I will use a recommended injector cleaner from this thread
4) Asked independent to fix it, he suggests full injector replacements but that is $1200 parts + labor ( I have no way of knowing if his price is above or below the market?)

Before you write off your vehicle and take a hit in your pocket book trading it in for something, I would see what the mechanic that you trust would quote you to fix what he thinks needs fixing. In addition to that, you could look at getting a tune, although I think you mentioned that you were hesitant to do that. Both of these options, independently, or together, would likely be less than the loss you will take trading in and you will still have the premium vehicle that you wanted. I get that GM is not going to do anything under warranty without a code, but that doesn't mean you have to give up on the vehicle.

 

[wjburken]

My wife agrees with you I promised her to try 4 things because she is mad at me for putting her into a time machine and transporting her into 1988 Yugo experience of a shaking car :
1) Mobil/Exxon gas (so far I am through the full tank but no change yet).
2) I will replace spark plugs and wires
3) I will use a recommended injector cleaner from this thread
4) Asked independent to fix it, he suggests full injector replacements but that is $1200 parts + labor ( I have no way of knowing if his price is above or below the market?)

No knowing how handy you are with working on cars, replacing injectors is not that difficult. It looks like RockAuto is out of stock, but pricing them at Tasca, you can get a set of GM Injectors for less than $600.
https://www.tascaparts.com/oem-parts/gm-s-injector-kit-12698484/?c=Zz1mdWVsLXN5c3RlbSZzPWZ1ZWwtc3lzdGVtLWNvbXBvbmVudHMmYT1nbWMmbz15dWtvbi14bCZ5PTIwMTgmdD1zbGUmZT01LTNsLXY4LWZsZXg=

 

[smokey_mountain]

I am reading that getting fuel rail is nearly impossible without special tools, I cannot find the good instructions but YouTube mechanics are saying it is HARD... I can wrench and do it with precision, as long as it does not require specialized tools that cost hundreds...

No knowing how handy you are with working on cars, replacing injectors is not that difficult. It looks like RockAuto is out of stock, but pricing them at Tasca, you can get a set of GM Injectors for less than $600.
https://www.tascaparts.com/oem-parts/gm-s-injector-kit-12698484/?c=Zz1mdWVsLXN5c3RlbSZzPWZ1ZWwtc3lzdGVtLWNvbXBvbmVudHMmYT1nbWMmbz15dWtvbi14bCZ5PTIwMTgmdD1zbGUmZT01LTNsLXY4LWZsZXg=