Air Measurement System
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With this condition, the engine runs rich or lean of stoichiometry (14.7:1 air to fuel ratio) if the PCM is not able to compensate enough to correct for the condition.
For example, the MAF sensor measurement is inaccurate due to a corroded connector, contaminated or dirty connector. A contaminated MAF sensor typically results in a rich system at low airflows (PCM reduces fuel) and a lean system at high airflows (PCM increases fuel).
With this condition, the engine runs rich or lean of stoichiometry (14.7:1 air to fuel ratio) if the PCM is not able to compensate enough to correct for the condition.