ok i kno this is old an all and been talked about many times but I’m stumped, 2004 z71 Tahoe I have a po300 code only, hooked scanner to it and shows cylinder 1 and 8.. have done all the regular things like everyone has.. plugs, wires, coil packs, fuel reg, fuel pump, cats.. I’m at a loss on this one. Anyone have any other ideas on it??
Po300 code only
- Thread starter Drewboy
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xjsc16x
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I've heard people say that the intake manifold gasket can cause this.
Tonyrodz
Resident Resident
Intake gaskets.
^^^ most likely, if you do the intake I would recommend the fel pro metalized gasket set
$48 at rockauto
https://www.rockauto.com/en/moreinfo.php?pk=1400245&cc=1424191&jsn=518&jsn=518&jsn=518
$48 at rockauto
https://www.rockauto.com/en/moreinfo.php?pk=1400245&cc=1424191&jsn=518&jsn=518&jsn=518
Joao GANDAREZ
TYF Newbie
I would do at least the pre cat o2s and give it a try. I had a really dumb issue. 02 took a crap all of a sudden one day. And got bank 2 lean . Random missfire. And ran like utter crap
sonic_the_hedgeh
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I had that problem with my 2004 Yukon Denali XL. I did some research and tried a can of Royal Purple max clean fuel system cleaner. Took about 2 days then the check engine light went off. Had it checked before and it was lean on both banks. I thought it was my injectors because it seemed very weak for a 6.0. After the light went off what a difference! I now have the power I should probably improved my fuel economy some as well.
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