Question about 1999 Mercury Cougar

2 Answers

Check engine light is on. I have replaced all oxygen sensors 1st. Then the light comes back on again. Codes tell me it is catalytic converter. I replace that. Drive half the day and it comes on again.

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2 Answers

The OBD2 Fault Codes you get from a Malfunction
Indicator Lamp (MIL) DO NOT TELL YOU WHAT IS
WRONG,OR WHAT TO REPLACE

Study OBD2 Systems.

Common Sense--why would you change all
O2 Sensors or a converter the should last 15 years ?

You take each code and go to a trouble chart & work
each code to find a problem,then come up with a solution,
and then the repair

What you did causes 2.3 Billion Dollars a year Worldwide,
in unnecessary parts purchases.

Posted on Mar 25, 2011

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  • 65 Answers

Did you replace both (2) oxygen sensors, the upstream and downstream. If its the converter throwing the code, you may be best off pulling it out completely and putting in a straight pipe depending on the state/province you are in, but I would try the other o2 sensor first.

Feedback appreciated.

Posted on Mar 25, 2011

  • Anonymous Mar 25, 2011

    Reilly---do live in the 1970's when converters first came out ?
    It is against Federal Laws to even remove a converter to replace
    it ,without filling out paperwork and returning the old one.

    With a straight pipe your vehicle won't run well, as you have no
    O2 Sensor Data,thus no way to adjust short term fuel trim !!
    Also you would have no consideration for the environment & polution

  • Darren Reilly
    Darren Reilly Mar 26, 2011

    pcsapp....I am only here to offer what help I can and you comment although are correct are also wrong. To say the comments you said are more hurtfull then anything, I want to let you know that the rules are different in CANADA then the United States, hence why I stated "depends on the state/province you are in" I am not here to challenge your expertise as I am sure you didnt intend to offend me with yours. Both answers are correct dependat upon where in the country you live. We have no such regulations regarding the c/converter here in Sask as they may have in the US. This comment you placed I feel is a personal attack on me personally, however I will not pursue this anyfurther, as I am confident once you read this you will agree...

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