An engine has excessive oxygen (O₂)readings at idle. At 2500 RPM, the readings are normal. Which condition is the most likely cause?

Name: An engine has excessive oxygen (O 2 )readings at idle. At 2500 RPM, the readings are normal. Which condition is the most likely cause?
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Question

Quizplus · Accepted Answer

A vacuum leak can cause excessive oxygen readings at idle because it allows extra air to enter the engine, leading to a lean condition. At higher RPMs, the effect of the vacuum leak is reduced, normalizing the oxygen readings.

An Engine Has Excessive Oxygen (O2)readings at Idle

An Engine Has Excessive Oxygen (O₂)readings at Idle