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Virtual Wrench
Virtual Wrench, Chevy Mechanic
Category: Chevy
Satisfied Customers: 14620
Experience:  35 years Master Mechanic
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2002 GMC Yukon Denali: 6.0L..Im getting a p300 and P0171 code

Customer Question

I have a 2002 GMC Yukon Denali 6.0L, I'm getting a P0300 and P0171 code, please help with your thoughts. Thanks.
Submitted: 8 years ago.
Category: Chevy
Expert:  Virtual Wrench replied 8 years ago.



P0300 means it has detected a misfire.


P0171 refers to lean fuel mixture.


I have included some info for you that explains it in detail. Basically it sounds like there is a vacuum leak in the engine area somewhere,,,the tricky part is finding it. I suggest looking around under the hood for and loose or disconnected vac hoses. You can also take a can of carb spray and lightly spray around different areas on the engine,,,wherever there are vac hoses,,,if you come across an area to where the idle increases, there is a vac leak. If nothing found,,,unfortunatly it will have to be hooked up to a factory level scan tool to isolate the culprit.





If you have any further questions, please feel free to reply.

If not, please click on ACCEPT

Thanks for asking!

Customer: replied 8 years ago.
Thanks for the info, thats what I expected. One last question then I will accept, is my 2002 GMC Yukon Denali 6.0L an LS1, LS2 or what I can't seem to determine which one. Thanks fot your help.
Expert:  Virtual Wrench replied 8 years ago.



According to my database its classified as a LS2..


Best of luck my friend!

Virtual Wrench and 2 other Chevy Specialists are ready to help you
Customer: replied 8 years ago.
V Wrench, Seems you are very knowledgeable, tell me if I'm wrong but doesn't the LS2 have an alum. block? Mine is an iron block.
Expert:  Virtual Wrench replied 8 years ago.

Hi there,


I just double checked and yes the LS2 has the alum block, used mainly in the corvette but could be special ordered for the Denali,,,sorry for the confusion.