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99 suburban miss fire


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  #1  
Old  March 18th, 2011, 7:56 AM
  • CF Beginner
    Join Date: Mar 2011
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    Derby Kansas
99 suburban miss fire

I am a first time poster here and have an issue with my 1999 suburban, 4wd, 5.7L, 153K. The engine light came on the other day after it had been idling a little rough. I went have the code read and the guy said that it was a miss fire on #6 cylinder. Are there any obvious things to check or look for? Is there a common issue that I should check first?

  #2  
Old  March 18th, 2011, 5:16 PM
  • CF Veteran
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Do a web search for trouble code P0306? It basically means cylinder #6 didn't contribute enough to the crankshaft output. Check for the usual suspects such as ignition and fuel injection components, and compression on that cylinder.

  #3  
Old  March 19th, 2011, 5:44 AM
  • CF Beginner
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    Great Falls, MT
I know this is gonna sound strange but my 99 Suburban had the exact thing and it turned out to be a leaking intake manifold gasket. apparently the Dex cool antifreeze ate the gaskets out. The problem was fixed with new gaskets and green antifreeze.

  #4  
Old  March 19th, 2011, 7:30 AM
  • CF Senior Member
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    Middletown DE
got that problem after changing/upgrading the intake manifold gaskets it turnout being a stuck poppet valve in the fuel injection spider i did the spider upgrade and cleaned the mass airflow sensor and it runs great now the fuel injection spider upgrade is worth every penny,check for spark and compression


Sean
1997 burb

  #5  
Old  March 20th, 2011, 11:39 AM
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    Derby Kansas
I have been losing coolant as well but no leak visible. So I guess that it is possible but how to tell for sure ?

  #6  
Old  March 20th, 2011, 8:36 PM
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    KC, MO area
Check around the water pump weep hole. If it's not coming out there, then it is either going into the crankcase or combustion chamber. Neither are good options.

  #7  
Old  March 20th, 2011, 9:24 PM
  • CF Junior Member
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    Ridgeway, Ontario, Canada
loneViper 
I know this is gonna sound strange but my 99 Suburban had the exact thing and it turned out to be a leaking intake manifold gasket. apparently the Dex cool antifreeze ate the gaskets out. The problem was fixed with new gaskets and green antifreeze.
I'm going down this road too. Can I ask you what it cost for that work? I was told $800. They do a couple of these every month.

  #8  
Old  March 20th, 2011, 9:28 PM
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    KC, MO area
If the antifreeze is getting in the oil for very long, then there'll be more to fix than just the gaskets.

  #9  
Old  March 21st, 2011, 5:16 AM
  • CF Beginner
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    Great Falls, MT
It's been a while since I had ours done but I do think it was in that $600 range. Course the Dex cool had to be flushed and green anti freeze installed. There is also a significant amount of labor. It deffinately cured the problem though. It would only be a matter of time before it got into the oil.


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