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02 540i cold start/rough Idle ...help!

Discussion in 'E39 (1997-2003)' started by Danny540i, Nov 8, 2010.

    Danny540i guest

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    My 2002 540i has 130,00 miles on it and I just started to have an Issue with the engine running rough, but only on a cold start up. Once the car reaches its normal temp. the car runs perfect with no hesitation or loss of power. I had never changed the spark plugs on the car since I got it with 70,000 miles and thought that the problem may lie there. So i bought new DNK spark plugs and boots and changed them, while in the process of doing so I noticed oil In and around the passenger side spark plugs. I cleaned it all up and gave the valve cover bolts a slight turn each in hope to stop the leak. when I was done, I started the car while it still being cold and noticed no difference with the Idle, the car still runs rough while cold. the check engine light however dose come on and off, with a code that links to a vent tank failure ?? no clue. so if anyone has some helpful Information It would be greatly appreciated.

    what has been done for the engine so far since I have had it.

    *water pump
    *alternator
    *belts
    *fuel filter
    *spark plugs
    *cleaned throttle body and maf sensor
    • Member

    dms540i

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    I would guess the CCV and valve cover gaskets need replacement. Both are pretty common - search is your friend.

    Danny540i guest

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    thank you, and i will look into the ccv. I also will change those valve cover gaskets as soon as I solve the Idle Issue.
    • Member
    • Technical Service Advisor

    mooseheadm5

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    I would also change the intake gaskets or do the "triple bypass" which consists of intake gaskets (including the vent valve/separator,) valve cover gaskets, and the valley pan gasket.

    Danny540i guest

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    Thanks paul for the Information. I will most likely be changeing what you recomended to me since I will be spending some time under the hood, I might as well get them out of the way while my hands are dirty.

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