Question about 1999 Mercury Cougar

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Want ilde changed the altrnater ,but everting back in .now the car will start but ildes rough if it ildes at all .

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  • wormy13 May 26, 2008

    it will run a little rough when you give it gas

  • wormy13 May 26, 2008

    battery is new ,could it be the oxyen sensor on the exust,at the maniflod

  • wormy13 May 27, 2008

    did a code check,had 4 sensor bad. the manifold air temp. sensor,idle air control valve,oxygen sensor and coil-ignition performance. THANK YOU

  • Anonymous Mar 17, 2014

    moisture problems in oil and intake


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How recently has it run well? if its been a while you may need to change out the fuel filter and clean the fuel system. Try the simplest first, fuel injector cleaner, regular tune up... If you are sure it has something to do with the electrical system then the cars computer should register a problem and give you a "check engine" light, if so then it would be possible to get the codes out of it to see which sensor to replace or where to plan further troubleshooting.  Remember if the alternator was bad at some point then the battery probably went with it, check the battery under load and replace it if needed. Also check the cabling harness to the battery to ensure it has a good connection. Pick up some contact cleaner from your local parts store and go though the electrical system to see if there is a corroded connection somewhere. Good Luck.

Posted on May 26, 2008

  • Will Kibler
    Will Kibler May 26, 2008

    if you are getting a check engine light the code readout would indicate the O2 sensor as the fault. You can try replacing it anyways.


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