Technician A says a low but steady idle vacuum reading indicates a sticking valve. Technician B says a fluctuating vacuum gauge reading indicates incorrect ignition timing. Which technician is correct?

Question

Quizplus · Accepted Answer

A low but steady idle vacuum reading typically indicates an issue like a vacuum leak or late ignition timing, not a sticking valve. A fluctuating vacuum gauge reading usually suggests a problem with valve operation, such as a sticking valve or misfiring cylinder, rather than incorrect ignition timing.

Technician a Says a Low but Steady Idle Vacuum Reading