failed smog test on 1995 Ford Aerostar

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?

by in Turlock, CA on September 07, 2010
1 answer 1 comment
ANSWER by on September 07, 2010
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 Roy
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COMMENT by on September 08, 2010
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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