Which of the following statements is LEAST-Likely true?
A) A leaner air-fuel mixture causes a higher resistance to spark, requiring more voltage to jump the plug gap.
B) A poorly performing cylinder with a high firing line can indicate a lean air-fuel mixture.
C) A poorly performing cylinder with a low firing line can indicate low compression.
D) You should run the engine at 800-1,000 rpm for oscilloscope tests.

Question

Quizplus · Accepted Answer

Oscilloscope tests for automotive diagnostics, including checking ignition waveforms, are typically conducted at idle speed, which is generally around 600-750 rpm for most vehicles, not the higher 800-1,000 rpm range. This ensures accurate readings without the influence of higher engine speeds.

Which of the Following Statements Is LEAST-Likely True