Final answer:
Tech A is correct because disabling a properly functioning cylinder will result in a noticeable drop in engine RPM. Tech B is not necessarily correct since disabling a faulty cylinder might not cause the engine to stall but will further reduce RPM or have minimal effect. The correct answer is Tech A.
Step-by-step explanation:
The question relates to an engine performance test, specifically a cylinder balance test used to identify a misfiring cylinder. In a cylinder balance test, disabling or 'cutting out' a cylinder is a common practice to observe the effect on engine performance. If a cylinder is operating properly, disabling it will cause a significant drop in engine RPM, given that cylinder's contribution to the engine's power is now absent. Therefore, Tech A is correct that when the faulty cylinder is disabled, the engine RPM will drop, but not necessarily more than for the other cylinders since the RPM drop should be approximately the same for all healthy cylinders. As for Tech B, disabling a faulty cylinder will not necessarily cause the engine to stall; it should simply reduce the RPM further or have little to no effect if that cylinder was not contributing significantly to begin with.