Question about 2003 Mercury Mountaineer

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I have a 2003 mercury mountaineer with 71,000 miles. It has been running fine until Friday evening when the service engine light went on. Mechanic told me that the #5 cylinder ignition coil had failed and recommended replacing all of them. He claimed that Ford has been having lots of problems with the ignition coils in their trucks. He replaced just the one. Tonight the service engine light went on again. Any thoughts?

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  • tedehret May 19, 2009

    V8. it had been running smoothly but when the engine service light went on I noticed some vibration coming from the engine compartment.

  • tedehret May 19, 2009

    Thanks very much. I will let you know what happens.

  • Flip Childs May 24, 2009

    2003 Mountaineer code P0302 rough idle lost of power

  • Mysticole_20 May 11, 2010

    how was the vehicles running while at speeds and idling?

  • buffalonyman
    buffalonyman May 11, 2010

    I would want the ignition coil to make sure it went bad. Usually defective coils **** out within a short period of time. If the ignition coil is bad, the vehicle would not be firing on that cyclinder and you would notice it


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Have it rescanned and see if it is the same code. What engine do you have?

Posted on May 19, 2009

  • Clint Smock
    Clint Smock May 19, 2009

    It is common for these coils to go bad, but I wouldn't just replace all of them. Have it rescanned to see if the same codes comes back. If it is the same code you can move coils to see if the miss moves also don't forget to check the plug on that cylinder also. Misfire code for cylinder 5 would be PO305.


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