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Pete, GMC Mechanic
Category: GMC
Satisfied Customers: 27647
Experience:  GM training and dealer tech for 14+ years. Diagnostics
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I have a 6.2 L v8 denali yukon fully loaded I am afraid my

Customer Question

I have a 6.2 L v8 denali yukon fully loaded I am afraid my mechanic is parting out some of its features but it still runs so jniw check engine codes are being thrown how do I get this checked into or what would be the best route to catch this and nip it in the butt. Thanks so very much also the engine runs very lean now and my exhaust used to roar. I hav4 lost a lot of the oower when excellerating as well ad the roar of my engine and exhuast. I am worried some of the features are missing but dnt kniw what to look for or how to check this
Submitted: 5 months ago.
Category: GMC
Expert:  Pete replied 5 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

When you say the mechanic is parting out some of its features can you describe what is or may be parted out?

Have you had fault codes checked at all?

Let me know,thanks Pete.

Customer: replied 5 months ago.
No I have not checked any codes I honestly do not kbow what for sure just that my denali is running so slow its almost like its running like a 4cl instead of a v8
Customer: replied 5 months ago.
I am asking becuase I do not know. I know my blower motor was changed and I can tell the ignition was accessed recently but that is all I have also my door was replaced and the wiring looked redone but I just needed a nee door handle does that kinda help
Customer: replied 5 months ago.
When I looked under the hood there is a lot of extra space looks like there is just a engine I could have swore it used to be crammed packed full of other parts under there
Customer: replied 5 months ago.
If I tak it to GMC will they be interested in looking it over and maybe answering my questions
Expert:  Pete replied 5 months ago.

O.k.,the first thing that needs done here is to have the fault codes read out/checked to see what codes are set.Once this is done any codes set need diagnosed to help locate and repair this issue here.I would have this done by a different shop or mechanic if your worried your current mechanic is tampering with anything.I would also have any repairs that this mechanic may have done re checked to make sure nothing was damaged or tampered with.

With the check engine light on there will be at least one code set.This will help diagnose and repair this issue here.Most shops or a dealer can read and diagnose the codes and in some cases a local parts store will read them at no charge to you but usually cannot diagnose the fault.Low power can be caused by a restricted catalytic converter in the exhaust,low fuel pressure from a weak fuel pump needing replaced or even a mass air flow sensor fault.This will have to be checked further to locate and repair this issue.

If components appear to be missing another mechanic should be able to look and tell you what is missing and what needs replaced.A dealer or any shop will do this for you.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 5 months ago.
Is there a way to reset these codes? Would advanced or auto zone be a good source?
Customer: replied 5 months ago.
He advised me not to drive a long distance. Also said he would come with me to advance or auto zone and have them read the codes said I woukd be wasting money taking to actual shop
Expert:  Pete replied 5 months ago.

Auto Zone will read out the codes and give you an idea of the fault at no charge but usually cannot diagnose and repair this.The codes to be diagnosed and repaired would have to be done by a shop or dealer or reputable mechanic.The only places that will actually reset the codes is a shop or dealer or reputable mechanic with a compatible scan tool that will work on your model here.

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete

Customer: replied 5 months ago.
This is why I am worried seems like bull crap excuses and he has managed his own autoshop and knows other shops around town so I feel he has easy access to screw me over
Customer: replied 5 months ago.
You never really answer my question tho what does the denali 08 come with standard for the 6.2 L what could be taken off and sold so that engine and all still functions just not at the top peak it use to
Expert:  Pete replied 5 months ago.

Yeah he shouldnt be saying that it is a waste of money to go to another shop.This sounds like he may be hiding something possibly but I cannot say this for sure.If it were me....I would have another mechanic or shop or dealer look into the codes as well if anything is tampered with or missing.Then determine from there on how you want to handle the repairs and see if it was the other mechanics fault.

The oxygen sensors can be removed causing this here as well as the mass air flow sensor.These can come off and cause this power issue here.

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete