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1995 Ford Aerostar Question: failed smog test



shadetreeauto, Turlock, CA, September 07, 2010, 19:43

my 4.0 aerostar has exsessive n. o. reading.i changed the mas sensor and the check engine lite is now out.what other repairs should i do before i retest it?

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  • Answer #1

    September 07, 2010, 19:49

    the mass air flow controls hc and co. nox is controlled by egr and cat converter. you had more than one problem. have these 2 items checked for operation


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    shadetreeauto, September 08, 2010, 13:42

    thanks for your reply.i was hoping not to replace the cats as they are high dollar.ill change the egr and see what i get.if it still wont pass ill have to take it to the referee.

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