Engine Performance (A8)Question 97 of 120
Technician A says a rich air-fuel mixture can raise tailpipe CO and HC. Technician B says the oxygen sensor helps the PCM keep the mixture near stoichiometric. Who is correct?
a.Technician A only
b.Technician B only
c.Both A and B
d.Neither A nor B
Explanation
A rich mixture leaves excess fuel that raises carbon monoxide and hydrocarbons, and the oxygen sensor feedback lets the PCM hold the mixture near the ideal ratio. Both technicians are correct. A lazy sensor degrades fuel control and emissions.
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