My 1992 Toyota Corolla All-Trac just failed the functional part of the smog test in California: when vacuum is applied to the EGR valve, the engine does not rough as it should. The question is: is the test tech’s explanation of why it failed plausible? He insists that under such circumstances, 99% of the time, the failure is not in the EGR valve itself but in [the connection from the EGR to] the intake manifold, which he says must have become clogged.
I am skeptical for a number of reasons: chief among them being his Vietnamese accent is so thick I can’t always tell what he is really trying to say, yet he is the one who gets impatient (answering questions with “I know what I am doing”) when I don’t understand him.