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?
failed smog test on 1995 Ford Aerostar
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
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.