Question about 1999 Chevrolet C2500

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PO300 code on 2004 Chevy 2500hd

I am having issues with the PO300 code showing up. The truck runs good and I only notice a slight miss at start up, other than this the truck runs fine. I have replaced the wires and plugs and the light still comes on. I can run around town for a while and I do not get the check engine light, it seems to come on while running the interstate at the higher rpm's.

Any help would be appreciated.

Frank K.

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  • Jerry Koski
    Jerry Koski May 11, 2010

    Hey frank make sure the rubber from the air cleaner to the maf sensor is tight and good connections are made from air cleaner to throttle body .. also you might clean that maf sensor .. like a screen with a little chemtool and then retighten it .. just a thought let me know. jerry thanks



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Hi Frank, Give me a call, 866-718-1234 ext 158.

Posted on Jul 13, 2009


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Does the engine show any physical issues such as loosing coolant, smoking exhaust, overheating? A blown or leaking head gasket on the #2 bank could also present these (among other)

Good luck and let me know how it goes!


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