Question about 2002 GMC Yukon Denali

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Rough Idle for the first couple of minutes then smooth...

For years now we have chased this problem down no one seems to be able to help. During the winter months the truck when started in the mornings First Start only has this problem. The truck will rev up and down until it stalls. imediately starts back up and slowly improves until no evidence of problem exists. Maybe 5 to 10 minutes. Even after the first start we can leave it outside in 10 degree weather for hours and will not be able to duplicate the problem. Only after it has sat over night will it duplicate the problem again. What we have done: O2 sensors, new plugs, Air Flow sensor, exhaust sensor. When engine light comes on states that it is miss firing and running too rich. Earlier this year fuel pump got replaced with new fuel filter. So we have got to be narrowing it down. I hope.

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  • bozdo Dec 08, 2008

    I had the same problem. Just got it fixed. Leaking intake manifold gasket

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1.-remove trottle body and clean it really good 2.-clean your EGR valve with some carb cleaner 3.-remove air intake pipe and clean MAF sensor with MASS AIR FLOW SENSOR CLEANER,make sure your air filter still in good condition. i did this on my 02 xl denali now the problem its gone!trust me!hope this helps on yours too

Posted on Dec 31, 2010

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It almost sounds like there is air getting into the throttle body...maybe a worn gasket is allowing air to get in until the truck has been running for a bit?

Posted on Dec 06, 2008

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